diff --git a/web/src/components/canvas/canvas-frame-node.tsx b/web/src/components/canvas/canvas-frame-node.tsx
index e8b2f2c9a..fa9ba016b 100644
--- a/web/src/components/canvas/canvas-frame-node.tsx
+++ b/web/src/components/canvas/canvas-frame-node.tsx
@@ -6,6 +6,7 @@ import { CometCard } from "@/components/ui/aceternity/comet-card";
 import { CanvasFolderPreview } from "@/components/canvas/canvas-folder-preview";
 import { CanvasVideoPreviewImage } from "@/components/canvas/canvas-video-preview-image";
 import { FRAME_HEADER_HEIGHT, FRAME_PADDING, isCanvasFolderNode } from "@/lib/canvas/canvas-frame";
+import type { CanvasNodeRenderLOD } from "@/lib/canvas/canvas-node-lod";
 import { canvasThemes, type CanvasTheme } from "@/lib/canvas-theme";
 import { useActiveTheme } from "@/stores/canvas/use-canvas-theme-store";
 import { CanvasNodeType, type CanvasFolderStyle, type CanvasFolderTheme, type CanvasNodeData, type Position } from "@/types/canvas";
@@ -14,6 +15,7 @@ type ResizeCorner = "top-left" | "top-right" | "bottom-left" | "bottom-right";
 
 export const CanvasFrameNode = React.memo(function CanvasFrameNode({
     data,
+    renderLOD = "full",
     dragOffset,
     childNodes,
     scale,
@@ -33,6 +35,7 @@ export const CanvasFrameNode = React.memo(function CanvasFrameNode({
     data: CanvasNodeData;
     dragOffset?: Position;
     childNodes: CanvasNodeData[];
+    renderLOD?: CanvasNodeRenderLOD;
     scale: number;
     isSelected: boolean;
     isDropTarget: boolean;
@@ -51,6 +54,7 @@ export const CanvasFrameNode = React.memo(function CanvasFrameNode({
     const collapsed = Boolean(data.metadata?.frame?.collapsed);
     const folder = isCanvasFolderNode(data);
     const [editing, setEditing] = useState(false);
+    const [hovered, setHovered] = useState(false);
     const [title, setTitle] = useState(data.title);
     const resizeRef = useRef({
         active: false,
@@ -148,10 +152,12 @@ export const CanvasFrameNode = React.memo(function CanvasFrameNode({
 
     const active = isSelected || isDropTarget;
     const linkedFolder = Boolean(data.metadata?.folder?.assetFolderId);
+    const fullDetail = renderLOD === "full" || hovered || editing;
 
     return (
         <div
             data-node-id={data.id}
+            data-node-lod={fullDetail ? "full" : renderLOD}
             role={folder && collapsed ? "group" : undefined}
             tabIndex={folder && collapsed ? 0 : undefined}
             aria-label={folder && collapsed ? `${data.title}，文件夹，${childNodes.length} 项内容。按回车打开` : undefined}
@@ -170,8 +176,8 @@ export const CanvasFrameNode = React.memo(function CanvasFrameNode({
                 event.preventDefault();
                 onToggleCollapsed(data.id);
             }}
-            onMouseEnter={() => onHoverStart?.(data.id)}
-            onMouseLeave={() => onHoverEnd?.(data.id)}
+            onMouseEnter={() => { setHovered(true); onHoverStart?.(data.id); }}
+            onMouseLeave={() => { setHovered(false); onHoverEnd?.(data.id); }}
         >
             {/* 帧节点同样禁用指针跟随 3D 位移，hover 使用 CSS 静态抬升 */}
             <CometCard
@@ -183,10 +189,14 @@ export const CanvasFrameNode = React.memo(function CanvasFrameNode({
                     background: folder && collapsed ? "transparent" : active ? theme.frame.activeFill : theme.frame.fill,
                     borderColor: folder && collapsed ? "transparent" : active ? theme.frame.activeStroke : theme.frame.stroke,
                     borderWidth: folder && collapsed ? 0 : 1 / Math.max(scale, 0.05),
-                    boxShadow: folder && collapsed ? "none" : isSelected ? `0 0 0 ${1 / Math.max(scale, 0.05)}px ${theme.frame.activeStroke}33, 0 24px 72px ${theme.spatial.shadow}` : `0 18px 54px ${theme.spatial.shadow}`,
+                    boxShadow: !fullDetail || (folder && collapsed) ? "none" : isSelected ? `0 0 0 ${1 / Math.max(scale, 0.05)}px ${theme.frame.activeStroke}33, 0 24px 72px ${theme.spatial.shadow}` : `0 18px 54px ${theme.spatial.shadow}`,
                 }}
             >
-                {folder && collapsed ? (
+                {!fullDetail ? (
+                    <div className="flex h-full items-center justify-center rounded-[var(--node-radius)]" style={{ background: theme.frame.fill, color: theme.node.text }}>
+                        {data.title} · {childNodes.length}
+                    </div>
+                ) : folder && collapsed ? (
                     // 素材库目录是单一事实源；画布节点只负责浏览和调用，避免本地改名后被同步结果覆盖。
                     <CanvasFolderPreview
                         data={data}
diff --git a/web/src/components/canvas/canvas-mini-map.tsx b/web/src/components/canvas/canvas-mini-map.tsx
index a0434f556..328181fcf 100644
--- a/web/src/components/canvas/canvas-mini-map.tsx
+++ b/web/src/components/canvas/canvas-mini-map.tsx
@@ -1,133 +1,87 @@
-import { useCallback, useEffect, useMemo, useRef, useState, type RefObject } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState, type PointerEvent as ReactPointerEvent, type RefObject } from "react";
 
-import { CachedResourceImage } from "@/components/cached-resource-image";
 import { canvasThemes } from "@/lib/canvas-theme";
 import { isFrameNode, isNodeHiddenByCollapsedFrame } from "@/lib/canvas/canvas-frame";
-import { buildLibTVImagePreviewUrl } from "@/lib/canvas/libtv-import";
-import { getNodeLabel } from "@/lib/canvas/node-registry/node-registry";
 import { subscribeCanvasViewportPreview } from "@/lib/canvas/canvas-live-viewport";
 import { useActiveTheme } from "@/stores/canvas/use-canvas-theme-store";
 import { CanvasNodeType, type CanvasNodeData, type ViewportTransform } from "@/types/canvas";
 
 const MINIMAP_WIDTH = 240;
 const MINIMAP_HEIGHT = 160;
-const MINIMAP_IMAGE_PREVIEW_LIMIT = 24;
 
-export function Minimap({ nodes, viewport, viewportSize, canvasContainerRef, onViewportPreviewChange, onViewportChange }: { nodes: CanvasNodeData[]; viewport: ViewportTransform; viewportSize: { width: number; height: number }; canvasContainerRef?: RefObject<HTMLDivElement | null>; onViewportPreviewChange?: (viewport: ViewportTransform) => void; onViewportChange: (viewport: ViewportTransform) => void }) {
+type MinimapProps = {
+    nodes: CanvasNodeData[];
+    viewport: ViewportTransform;
+    viewportSize: { width: number; height: number };
+    canvasContainerRef?: RefObject<HTMLDivElement | null>;
+    onViewportPreviewChange?: (viewport: ViewportTransform) => void;
+    onViewportChange: (viewport: ViewportTransform) => void;
+};
+
+export function Minimap({ nodes, viewport, viewportSize, canvasContainerRef, onViewportPreviewChange, onViewportChange }: MinimapProps) {
     const theme = canvasThemes[useActiveTheme()];
     const containerRef = useRef<HTMLDivElement>(null);
-    const viewportRectRef = useRef<HTMLDivElement>(null);
+    const canvasRef = useRef<HTMLCanvasElement>(null);
     const liveViewportRef = useRef(viewport);
     const [isDragging, setIsDragging] = useState(false);
     const width = MINIMAP_WIDTH;
     const height = MINIMAP_HEIGHT;
     const displayNodes = useMemo(() => nodes.filter((node) => !isNodeHiddenByCollapsedFrame(node, nodes)), [nodes]);
-    const showImagePreviews = useMemo(() => displayNodes.filter((node) => node.type === CanvasNodeType.Image && Boolean(getImagePreviewSource(node) || node.metadata?.storageKey)).length <= MINIMAP_IMAGE_PREVIEW_LIMIT, [displayNodes]);
-
     const { worldBounds, scale, offset } = useMemo(() => {
-        if (!displayNodes.length) {
-            return { worldBounds: { x: -500, y: -500, w: 1000, h: 1000 }, scale: 0.16, offset: { x: 40, y: 0 } };
-        }
-
+        if (!displayNodes.length) return { worldBounds: { x: -500, y: -500, w: 1000, h: 1000 }, scale: 0.16, offset: { x: 40, y: 0 } };
         let minX = Infinity;
         let minY = Infinity;
         let maxX = -Infinity;
         let maxY = -Infinity;
-
         displayNodes.forEach((node) => {
             minX = Math.min(minX, node.position.x);
             minY = Math.min(minY, node.position.y);
             maxX = Math.max(maxX, node.position.x + node.width);
             maxY = Math.max(maxY, node.position.y + node.height);
         });
-
         minX -= 500;
         minY -= 500;
         maxX += 500;
         maxY += 500;
-
-        const boundsWidth = maxX - minX;
-        const boundsHeight = maxY - minY;
+        const boundsWidth = Math.max(maxX - minX, 1);
+        const boundsHeight = Math.max(maxY - minY, 1);
         const nextScale = Math.min(width / boundsWidth, height / boundsHeight);
-        const mapContentW = boundsWidth * nextScale;
-        const mapContentH = boundsHeight * nextScale;
-
         return {
             worldBounds: { x: minX, y: minY, w: boundsWidth, h: boundsHeight },
             scale: nextScale,
-            offset: { x: (width - mapContentW) / 2, y: (height - mapContentH) / 2 },
+            offset: { x: (width - boundsWidth * nextScale) / 2, y: (height - boundsHeight * nextScale) / 2 },
         };
-    }, [displayNodes]);
-
-    const toMinimap = useCallback(
-        (worldX: number, worldY: number) => {
-            return {
-                x: (worldX - worldBounds.x) * scale + offset.x,
-                y: (worldY - worldBounds.y) * scale + offset.y,
-            };
-        },
-        [offset.x, offset.y, scale, worldBounds.x, worldBounds.y],
-    );
-
-    const toWorld = useCallback(
-        (minimapX: number, minimapY: number) => {
-            return {
-                x: (minimapX - offset.x) / scale + worldBounds.x,
-                y: (minimapY - offset.y) / scale + worldBounds.y,
-            };
-        },
-        [offset.x, offset.y, scale, worldBounds.x, worldBounds.y],
-    );
-
+    }, [displayNodes, height, width]);
+    const toMinimap = useCallback((worldX: number, worldY: number) => ({ x: (worldX - worldBounds.x) * scale + offset.x, y: (worldY - worldBounds.y) * scale + offset.y }), [offset.x, offset.y, scale, worldBounds.x, worldBounds.y]);
+    const toWorld = useCallback((minimapX: number, minimapY: number) => ({ x: (minimapX - offset.x) / scale + worldBounds.x, y: (minimapY - offset.y) / scale + worldBounds.y }), [offset.x, offset.y, scale, worldBounds.x, worldBounds.y]);
     const viewportRect = useMemo(() => {
         const vx = -viewport.x / viewport.k;
         const vy = -viewport.y / viewport.k;
-        const vw = viewportSize.width / viewport.k;
-        const vh = viewportSize.height / viewport.k;
         const p1 = toMinimap(vx, vy);
-        const p2 = toMinimap(vx + vw, vy + vh);
-
-        return {
-            x: p1.x,
-            y: p1.y,
-            w: Math.max(p2.x - p1.x, 4),
-            h: Math.max(p2.y - p1.y, 4),
-        };
+        const p2 = toMinimap(vx + viewportSize.width / viewport.k, vy + viewportSize.height / viewport.k);
+        return { x: p1.x, y: p1.y, w: Math.max(p2.x - p1.x, 4), h: Math.max(p2.y - p1.y, 4) };
     }, [toMinimap, viewport.k, viewport.x, viewport.y, viewportSize.height, viewportSize.width]);
-
     const updateViewportRect = useCallback((nextViewport: ViewportTransform) => {
         liveViewportRef.current = nextViewport;
-        const element = viewportRectRef.current;
-        if (!element) return;
-        const vx = -nextViewport.x / nextViewport.k;
-        const vy = -nextViewport.y / nextViewport.k;
-        const p1 = toMinimap(vx, vy);
-        const p2 = toMinimap(vx + viewportSize.width / nextViewport.k, vy + viewportSize.height / nextViewport.k);
-        element.style.left = `${p1.x}px`;
-        element.style.top = `${p1.y}px`;
-        element.style.width = `${Math.max(p2.x - p1.x, 4)}px`;
-        element.style.height = `${Math.max(p2.y - p1.y, 4)}px`;
-    }, [toMinimap, viewportSize.height, viewportSize.width]);
+        drawMinimap(canvasRef.current, displayNodes, toMinimap, nextViewport, viewportSize, theme);
+    }, [displayNodes, theme, toMinimap, viewportSize]);
 
+    useEffect(() => {
+        drawMinimap(canvasRef.current, displayNodes, toMinimap, viewport, viewportSize, theme);
+    }, [displayNodes, theme, toMinimap, viewport, viewportSize]);
     useEffect(() => updateViewportRect(viewport), [updateViewportRect, viewport]);
-
     useEffect(() => {
         const canvasContainer = canvasContainerRef?.current;
         if (!canvasContainer) return;
         return subscribeCanvasViewportPreview(canvasContainer, updateViewportRect);
     }, [canvasContainerRef, updateViewportRect]);
 
-    const updateViewportFromEvent = (event: React.PointerEvent) => {
+    const updateViewportFromEvent = (event: ReactPointerEvent) => {
         const rect = containerRef.current?.getBoundingClientRect();
         if (!rect) return;
-
         const world = toWorld(event.clientX - rect.left, event.clientY - rect.top);
-        const scale = liveViewportRef.current.k;
-        const next = {
-            x: viewportSize.width / 2 - world.x * scale,
-            y: viewportSize.height / 2 - world.y * scale,
-            k: scale,
-        };
+        const current = liveViewportRef.current;
+        const next = { x: viewportSize.width / 2 - world.x * current.k, y: viewportSize.height / 2 - world.y * current.k, k: current.k };
         liveViewportRef.current = next;
         onViewportPreviewChange?.(next);
     };
@@ -155,59 +109,37 @@ export function Minimap({ nodes, viewport, viewportSize, canvasContainerRef, onV
                     onViewportChange(liveViewportRef.current);
                 }}
             >
-                {displayNodes.map((node) => {
-                    const pos = toMinimap(node.position.x, node.position.y);
-                    const frame = isFrameNode(node);
-                    const color = node.type === CanvasNodeType.Image ? "#10b981" : node.type === CanvasNodeType.Video ? "#f97316" : node.type === CanvasNodeType.Audio ? "#a855f7" : node.type === CanvasNodeType.Config ? "#60a5fa" : node.type === CanvasNodeType.Skill ? "#818cf8" : frame ? theme.frame.stroke : theme.node.muted;
-                    const imagePreviewSource = showImagePreviews && node.type === CanvasNodeType.Image ? getImagePreviewSource(node) : "";
-                    const nodeLabel = node.title?.trim() || getNodeLabel(node.type);
-                    return (
-                        <div
-                            key={node.id}
-                            className="absolute rounded-[1px]"
-                            style={{
-                                left: pos.x,
-                                top: pos.y,
-                                width: Math.max(node.width * scale, 2),
-                                height: Math.max(node.height * scale, 2),
-                                backgroundColor: frame ? (node.metadata?.frame?.collapsed ? theme.frame.preview : "transparent") : color,
-                                border: frame ? `1px solid ${color}` : undefined,
-                                opacity: frame ? 0.95 : 0.8,
-                            }}
-                        >
-                            <div className="absolute inset-0 overflow-hidden rounded-[1px]">
-                                {imagePreviewSource || (showImagePreviews && node.type === CanvasNodeType.Image && node.metadata?.storageKey) ? (
-                                    <CachedResourceImage
-                                        storageKey={node.metadata?.storageKey}
-                                        src={imagePreviewSource}
-                                        alt=""
-                                        loading="lazy"
-                                        decoding="async"
-                                        draggable={false}
-                                        className="size-full object-cover"
-                                        fallback={null}
-                                    />
-                                ) : null}
-                            </div>
-                            <span
-                                title={nodeLabel}
-                                aria-label={nodeLabel}
-                                className="pointer-events-none absolute left-0 top-0 z-[1] max-w-[7.5rem] -translate-y-1/2 truncate whitespace-nowrap rounded-[2px] border px-1 py-px text-[9px] font-medium leading-[1.15] shadow-sm"
-                                style={{ color: theme.node.text, background: theme.toolbar.panel, borderColor: theme.toolbar.border }}
-                            >
-                                {nodeLabel}
-                            </span>
-                        </div>
-                    );
-                })}
-                <div ref={viewportRectRef} className="pointer-events-none absolute rounded-[var(--r-xs)]" style={{ left: viewportRect.x, top: viewportRect.y, width: viewportRect.w, height: viewportRect.h, background: `${theme.node.activeStroke}12`, boxShadow: `inset 0 0 0 1px ${theme.node.activeStroke}66` }} />
+                <canvas ref={canvasRef} width={width} height={height} className="pointer-events-none block size-full" aria-label="画布小地图" />
+                <div className="pointer-events-none absolute rounded-[var(--r-xs)]" style={{ left: viewportRect.x, top: viewportRect.y, width: viewportRect.w, height: viewportRect.h, background: `${theme.node.activeStroke}12`, boxShadow: `inset 0 0 0 1px ${theme.node.activeStroke}66` }} />
             </div>
         </div>
     );
 }
 
-function getImagePreviewSource(node: CanvasNodeData) {
-    if (node.type !== CanvasNodeType.Image) return "";
-    const content = node.metadata?.content || "";
-    return node.metadata?.previewContent || (node.metadata?.importSource?.provider === "libtv" ? buildLibTVImagePreviewUrl(content) : content);
+function drawMinimap(canvas: HTMLCanvasElement | null, nodes: CanvasNodeData[], toMinimap: (x: number, y: number) => { x: number; y: number }, viewport: ViewportTransform, viewportSize: { width: number; height: number }, theme: (typeof canvasThemes)[keyof typeof canvasThemes]) {
+    if (!canvas) return;
+    const context = canvas.getContext("2d");
+    if (!context) return;
+    context.clearRect(0, 0, canvas.width, canvas.height);
+    for (const node of nodes) {
+        const pos = toMinimap(node.position.x, node.position.y);
+        const frame = isFrameNode(node);
+        const color = node.type === CanvasNodeType.Image ? "#10b981" : node.type === CanvasNodeType.Video ? "#f97316" : node.type === CanvasNodeType.Audio ? "#a855f7" : node.type === CanvasNodeType.Config ? "#60a5fa" : node.type === CanvasNodeType.Skill ? "#818cf8" : frame ? theme.frame.stroke : theme.node.muted;
+        const p2 = toMinimap(node.position.x + node.width, node.position.y + node.height);
+        const rectWidth = Math.max(p2.x - pos.x, 2);
+        const rectHeight = Math.max(p2.y - pos.y, 2);
+        context.globalAlpha = frame ? 0.95 : 0.8;
+        context.fillStyle = frame && !node.metadata?.frame?.collapsed ? "transparent" : color;
+        context.strokeStyle = color;
+        context.lineWidth = frame ? 1 : 0;
+        if (context.fillStyle !== "transparent") context.fillRect(pos.x, pos.y, rectWidth, rectHeight);
+        if (frame) context.strokeRect(pos.x, pos.y, rectWidth, rectHeight);
+    }
+    const vx = -viewport.x / viewport.k;
+    const vy = -viewport.y / viewport.k;
+    const p1 = toMinimap(vx, vy);
+    const p2 = toMinimap(vx + viewportSize.width / viewport.k, vy + viewportSize.height / viewport.k);
+    context.globalAlpha = 1;
+    context.strokeStyle = theme.node.activeStroke;
+    context.strokeRect(p1.x, p1.y, Math.max(p2.x - p1.x, 4), Math.max(p2.y - p1.y, 4));
 }
diff --git a/web/src/components/canvas/canvas-node-content.tsx b/web/src/components/canvas/canvas-node-content.tsx
index e01a4ee2a..9e6806f3c 100644
--- a/web/src/components/canvas/canvas-node-content.tsx
+++ b/web/src/components/canvas/canvas-node-content.tsx
@@ -1,9 +1,12 @@
-import { useCallback, useEffect, useMemo, useRef, useState, type CSSProperties, type ReactNode, type RefObject } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState, useSyncExternalStore, type CSSProperties, type ReactNode, type RefObject } from "react";
+import { idleTaskTickerSubscribe, subscribeTaskTicker, taskTickerSnapshot } from "@/lib/canvas/task-ticker";
 import { AlertCircle, BookOpenCheck, Clock3, Download, FileText, Image as ImageIcon, LoaderCircle, Music2, Pencil, Play, RefreshCw, Video } from "lucide-react";
 
 import { VideoPlayer } from "@/components/video-player";
 import { CONTENT_MODERATION_ERROR_CODE, generationErrorMessage, isContentModerationError } from "@/lib/generation-error";
 import { generationTaskShowsProgress, generationTaskStageLabel, generationTaskStatusLabel, isGenerationTaskSubmissionUncertain } from "@/lib/generation-task-display";
+import type { CanvasNodeRenderLOD } from "@/lib/canvas/canvas-node-lod";
+import { CachedResourceImage } from "@/components/cached-resource-image";
 import { canvasRichTextHTML } from "@/lib/canvas/canvas-rich-text";
 import { fitNodeSize } from "@/lib/canvas/canvas-node-size";
 import { canvasTextFontSize } from "@/lib/canvas/canvas-text-scale";
@@ -15,7 +18,6 @@ import type { CanvasResourceReference } from "@/lib/canvas/canvas-resource-refer
 import type { CanvasTheme } from "@/lib/canvas-theme";
 import { formatBytes } from "@/lib/image-utils";
 import type { GenerationTask } from "@/services/api/task-center";
-import { scheduleResourceBlobCache } from "@/services/resource-blob-cache";
 import { resolveMediaUrl } from "@/services/file-storage";
 import { hydrateCanvasVideoPreview } from "@/services/canvas-video-preview";
 import { CanvasNodeType, type CanvasNodeData } from "@/types/canvas";
@@ -42,6 +44,7 @@ import { MEDIA_CONVERSION_NODE_TYPE } from "@/lib/media-conversion/contracts";
 export type CanvasNodeContentProps = {
     node: CanvasNodeData;
     theme: CanvasTheme;
+    renderLOD?: CanvasNodeRenderLOD;
     isEditingContent: boolean;
     textareaRef: RefObject<HTMLTextAreaElement | null>;
     isBatchRoot: boolean;
@@ -65,14 +68,17 @@ export type CanvasNodeContentProps = {
 };
 
 export function CanvasNodeContent(props: CanvasNodeContentProps) {
+    if (props.renderLOD === "shell") return <CanvasNodeShellContent node={props.node} theme={props.theme} />;
+    if (props.renderLOD === "preview") return <CanvasNodePreviewContent node={props.node} theme={props.theme} />;
     if (props.node.metadata?.fileUpload) return <CanvasFileUploadContent node={props.node} theme={props.theme} reduceMotion={props.reduceMediaEffects} />;
-    const hasCustomContent = props.node.type === CanvasNodeType.Config
-        || props.node.type === CanvasNodeType.Script
-        || props.node.type === CanvasNodeType.BatchTable
-        || Boolean(props.node.metadata?.directorSceneId)
-        || (props.node.metadata?.workflowKind === "character" && Boolean(props.node.metadata.characterAssetId))
-        || (props.node.metadata?.workflowKind === "story_input" && !props.isEditingContent)
-        || (props.node.metadata?.workflowKind === "styleboard" && !props.node.metadata.content);
+    const hasCustomContent =
+        props.node.type === CanvasNodeType.Config ||
+        props.node.type === CanvasNodeType.Script ||
+        props.node.type === CanvasNodeType.BatchTable ||
+        Boolean(props.node.metadata?.directorSceneId) ||
+        (props.node.metadata?.workflowKind === "character" && Boolean(props.node.metadata.characterAssetId)) ||
+        (props.node.metadata?.workflowKind === "story_input" && !props.isEditingContent) ||
+        (props.node.metadata?.workflowKind === "styleboard" && !props.node.metadata.content);
     if (hasCustomContent && props.renderNodeContent) return props.renderNodeContent(props.node);
     if (props.node.type === ART_CRITIQUE_NODE_TYPE) return <ArtCritiqueNodeContent node={props.node} />;
     if (props.node.type === MEDIA_CONVERSION_NODE_TYPE) return <MediaConversionNodeContent node={props.node} theme={props.theme} />;
@@ -86,20 +92,50 @@ export function CanvasNodeContent(props: CanvasNodeContentProps) {
     return Renderer ? <Renderer {...props} /> : <UnknownNodeContent theme={props.theme} />;
 }
 
+function CanvasNodeShellContent({ node, theme }: { node: CanvasNodeData; theme: CanvasTheme }) {
+    const Icon = node.type === CanvasNodeType.Video ? Video : node.type === CanvasNodeType.Audio ? Music2 : node.type === CanvasNodeType.Image ? ImageIcon : FileText;
+    return (
+        <div className="flex size-full flex-col items-center justify-center gap-2 rounded-[var(--node-radius)] px-3 text-center" style={{ background: theme.node.fill, color: theme.node.muted }}>
+            <Icon className="size-6 opacity-40" />
+            <span className="max-w-full truncate text-xs font-medium" title={node.title}>{node.title || "画布节点"}</span>
+        </div>
+    );
+}
+
+function CanvasNodePreviewContent({ node, theme }: { node: CanvasNodeData; theme: CanvasTheme }) {
+    if (node.type === CanvasNodeType.Image && (node.metadata?.content || node.metadata?.storageKey)) {
+        return <CachedResourceImage storageKey={node.metadata?.storageKey} src={node.metadata?.previewContent || node.metadata?.content} alt={node.title} loading="lazy" decoding="async" draggable={false} className="pointer-events-none block size-full select-none object-contain" fallback={<CanvasNodeShellContent node={node} theme={theme} />} />;
+    }
+    if (node.type === CanvasNodeType.Video && (node.metadata?.content || node.metadata?.storageKey)) {
+        return <CanvasVideoPreviewImage node={node} alt={node.title} loading="lazy" decoding="async" draggable={false} className="pointer-events-none block size-full select-none object-contain" fallback={<CanvasNodeShellContent node={node} theme={theme} />} />;
+    }
+    return <CanvasNodeShellContent node={node} theme={theme} />;
+}
+
 function PluginCanvasNodeContent({ node, theme, renderer, schema }: CanvasNodeContentProps & { renderer: "declarative" | "sandbox"; schema: Record<string, unknown> }) {
     if (renderer === "sandbox") {
-        return <div className="flex h-full w-full items-center justify-center p-4 text-center text-xs" style={{ color: theme.node.placeholder }}>
-            插件节点等待隔离运行时
-        </div>;
+        return (
+            <div className="flex h-full w-full items-center justify-center p-4 text-center text-xs" style={{ color: theme.node.placeholder }}>
+                插件节点等待隔离运行时
+            </div>
+        );
     }
     const data = node.metadata?.pluginData || {};
-    const fields = Object.keys(schema.properties && typeof schema.properties === "object" ? schema.properties as Record<string, unknown> : schema);
-    return <div className="flex h-full w-full flex-col gap-3 overflow-auto p-4 pt-10 text-xs" style={{ color: theme.node.text }}>
-        {fields.length ? fields.map((field) => <div key={field} className="flex flex-col gap-1">
-            <span className="font-medium opacity-60">{field}</span>
-            <span className="whitespace-pre-wrap break-words opacity-90">{formatPluginValue(data[field] ?? (field === "content" ? node.metadata?.content : undefined))}</span>
-        </div>) : <span className="whitespace-pre-wrap break-words">{node.metadata?.content || "插件节点"}</span>}
-    </div>;
+    const fields = Object.keys(schema.properties && typeof schema.properties === "object" ? (schema.properties as Record<string, unknown>) : schema);
+    return (
+        <div className="flex h-full w-full flex-col gap-3 overflow-auto p-4 pt-10 text-xs" style={{ color: theme.node.text }}>
+            {fields.length ? (
+                fields.map((field) => (
+                    <div key={field} className="flex flex-col gap-1">
+                        <span className="font-medium opacity-60">{field}</span>
+                        <span className="whitespace-pre-wrap break-words opacity-90">{formatPluginValue(data[field] ?? (field === "content" ? node.metadata?.content : undefined))}</span>
+                    </div>
+                ))
+            ) : (
+                <span className="whitespace-pre-wrap break-words">{node.metadata?.content || "插件节点"}</span>
+            )}
+        </div>
+    );
 }
 
 function formatPluginValue(value: unknown) {
@@ -138,15 +174,17 @@ function DrawingContent({ node, theme, drawingProjectId }: CanvasNodeContentProp
         if (!drawingProjectId || !drawingId) return;
         let active = true;
         let objectUrl = "";
-        void loadCanvasDrawingPreview(drawingProjectId, drawingId).then((preview) => {
-            if (!active) return;
-            if (!preview) {
-                setPreviewUrl(fallbackPreview);
-                return;
-            }
-            objectUrl = URL.createObjectURL(preview);
-            setPreviewUrl(objectUrl);
-        }).catch((error) => console.warn("读取绘图节点预览失败", error));
+        void loadCanvasDrawingPreview(drawingProjectId, drawingId)
+            .then((preview) => {
+                if (!active) return;
+                if (!preview) {
+                    setPreviewUrl(fallbackPreview);
+                    return;
+                }
+                objectUrl = URL.createObjectURL(preview);
+                setPreviewUrl(objectUrl);
+            })
+            .catch((error) => console.warn("读取绘图节点预览失败", error));
         return () => {
             active = false;
             if (objectUrl) URL.revokeObjectURL(objectUrl);
@@ -169,8 +207,12 @@ function DrawingContent({ node, theme, drawingProjectId }: CanvasNodeContentProp
             )}
             <div className="pointer-events-none absolute inset-x-0 bottom-0 flex items-end justify-between gap-3 px-4 pb-3 pt-12" style={{ background: `linear-gradient(to top, ${theme.node.fill}, ${theme.node.fill}e6 55%, transparent)` }}>
                 <div className="min-w-0">
-                    <div className="truncate text-xs font-semibold" title={node.title || "绘图"}>{node.title || "绘图"}</div>
-                    <div className="mt-0.5 text-[var(--fs-tiny)]" style={{ color: theme.node.muted }}>{shapeCount} 个图形 · {pageCount} 个页面</div>
+                    <div className="truncate text-xs font-semibold" title={node.title || "绘图"}>
+                        {node.title || "绘图"}
+                    </div>
+                    <div className="mt-0.5 text-[var(--fs-tiny)]" style={{ color: theme.node.muted }}>
+                        {shapeCount} 个图形 · {pageCount} 个页面
+                    </div>
                 </div>
                 <Pencil className="size-3.5 shrink-0" style={{ color: theme.accent.primary }} />
             </div>
@@ -210,10 +252,23 @@ function LoadingContent({ node, theme, onOpenTaskDetails }: Pick<CanvasNodeConte
                         </div>
                     ) : null}
                     <div className="max-w-full truncate text-[var(--fs-tiny)] tabular-nums" style={{ color: theme.node.muted }}>
-                        <Clock3 className="mr-1 inline size-3" />{elapsed} · {shortTaskId(taskId)}
+                        <Clock3 className="mr-1 inline size-3" />
+                        {elapsed} · {shortTaskId(taskId)}
                     </div>
                     <div className="mt-0.5 flex items-center gap-1.5">
-                        <button type="button" className="inline-flex h-7 items-center gap-1 rounded-[var(--r-sm)] px-2 text-[var(--fs-tiny)] font-medium transition-colors" style={{ background: theme.toolbar.itemHover, color: theme.node.text }} onMouseDown={(event) => event.stopPropagation()} onClick={(event) => { event.stopPropagation(); onOpenTaskDetails?.(node); }}><FileText className="size-3" />详情</button>
+                        <button
+                            type="button"
+                            className="inline-flex h-7 items-center gap-1 rounded-[var(--r-sm)] px-2 text-[var(--fs-tiny)] font-medium transition-colors"
+                            style={{ background: theme.toolbar.itemHover, color: theme.node.text }}
+                            onMouseDown={(event) => event.stopPropagation()}
+                            onClick={(event) => {
+                                event.stopPropagation();
+                                onOpenTaskDetails?.(node);
+                            }}
+                        >
+                            <FileText className="size-3" />
+                            详情
+                        </button>
                     </div>
                 </div>
             ) : null}
@@ -222,14 +277,11 @@ function LoadingContent({ node, theme, onOpenTaskDetails }: Pick<CanvasNodeConte
 }
 
 function useTaskElapsed(createdAt?: string) {
-    const [, setTick] = useState(0);
-    useEffect(() => {
-        if (!createdAt) return;
-        const timer = window.setInterval(() => setTick((value) => value + 1), 1000);
-        return () => window.clearInterval(timer);
-    }, [createdAt]);
+    const now = useSyncExternalStore(createdAt ? subscribeTaskTicker : idleTaskTickerSubscribe, taskTickerSnapshot, taskTickerSnapshot);
     if (!createdAt) return "刚刚";
-    const seconds = Math.max(0, Math.floor((Date.now() - new Date(createdAt).getTime()) / 1000));
+    const started = new Date(createdAt).getTime();
+    if (!Number.isFinite(started)) return "刚刚";
+    const seconds = Math.max(0, Math.floor((now - started) / 1000));
     if (seconds < 60) return `${seconds}秒`;
     const minutes = Math.floor(seconds / 60);
     return minutes < 60 ? `${minutes}分${seconds % 60}秒` : `${Math.floor(minutes / 60)}时${minutes % 60}分`;
@@ -253,7 +305,9 @@ function ErrorContent({ node, theme, onRetry, onReloadResource }: Pick<CanvasNod
     const submissionUncertain = isGenerationTaskSubmissionUncertain(errorDisplayTask);
     return (
         <div className="flex max-w-[260px] flex-col items-center gap-3 px-5 text-center">
-            <div className="text-xs leading-5" style={{ color: submissionUncertain ? theme.node.text : theme.accent.danger }}>{submissionUncertain ? generationTaskStatusLabel(errorDisplayTask) : generationErrorMessage(node.metadata?.errorDetails)}</div>
+            <div className="text-xs leading-5" style={{ color: submissionUncertain ? theme.node.text : theme.accent.danger }}>
+                {submissionUncertain ? generationTaskStatusLabel(errorDisplayTask) : generationErrorMessage(node.metadata?.errorDetails)}
+            </div>
             {submissionUncertain ? (
                 <div className="rounded-[var(--r-sm)] px-3 py-2 text-[var(--fs-label)] leading-4" style={{ background: theme.toolbar.itemHover, color: theme.node.muted }}>
                     {generationTaskStageLabel(errorDisplayTask)}
@@ -268,7 +322,10 @@ function ErrorContent({ node, theme, onRetry, onReloadResource }: Pick<CanvasNod
                         type="button"
                         className="inline-flex h-8 items-center gap-1.5 rounded-[var(--r-md)] px-3 text-xs font-medium transition-colors"
                         style={{ background: theme.accent.primary, color: theme.accent.onPrimary }}
-                        onClick={(event) => { event.stopPropagation(); onReloadResource?.(node); }}
+                        onClick={(event) => {
+                            event.stopPropagation();
+                            onReloadResource?.(node);
+                        }}
                         onMouseDown={(event) => event.stopPropagation()}
                     >
                         <Download className="size-3.5" />
@@ -278,7 +335,10 @@ function ErrorContent({ node, theme, onRetry, onReloadResource }: Pick<CanvasNod
                         type="button"
                         className="inline-flex h-8 items-center gap-1.5 rounded-[var(--r-md)] px-3 text-xs font-medium transition-colors"
                         style={{ background: theme.toolbar.itemHover, color: theme.node.text }}
-                        onClick={(event) => { event.stopPropagation(); onRetry?.(node); }}
+                        onClick={(event) => {
+                            event.stopPropagation();
+                            onRetry?.(node);
+                        }}
                         onMouseDown={(event) => event.stopPropagation()}
                     >
                         <RefreshCw className="size-3.5" />
@@ -305,7 +365,11 @@ function ErrorContent({ node, theme, onRetry, onReloadResource }: Pick<CanvasNod
 }
 
 function UnknownNodeContent({ theme }: Pick<CanvasNodeContentProps, "theme">) {
-    return <div className="flex h-full w-full items-center justify-center text-sm" style={{ color: theme.node.placeholder }}>未知节点</div>;
+    return (
+        <div className="flex h-full w-full items-center justify-center text-sm" style={{ color: theme.node.placeholder }}>
+            未知节点
+        </div>
+    );
 }
 
 function TextContent({ node, theme, isEditingContent, textareaRef, mentionReferences, onContentChange, onStopEditing }: CanvasNodeContentProps) {
@@ -362,22 +426,45 @@ function SkillContent({ node, theme }: CanvasNodeContentProps) {
                             <BookOpenCheck className="size-4" />
                         </span>
                         <div className="min-w-0">
-                            <div className="truncate text-sm font-semibold" title={skill?.name || node.title || "技能"}>{skill?.name || node.title || "技能"}</div>
+                            <div className="truncate text-sm font-semibold" title={skill?.name || node.title || "技能"}>
+                                {skill?.name || node.title || "技能"}
+                            </div>
                             <div className="mt-0.5 flex items-center gap-1.5 text-[var(--fs-label)]" style={{ color: theme.node.muted }}>
-                                <span>{skillCategoryLabel(skill?.category)}</span><span>·</span><span>{skillOutputModeLabel(skill?.outputMode)}</span>
-                                {skill?.version ? <><span>·</span><span>v{skill.version}</span></> : null}
+                                <span>{skillCategoryLabel(skill?.category)}</span>
+                                <span>·</span>
+                                <span>{skillOutputModeLabel(skill?.outputMode)}</span>
+                                {skill?.version ? (
+                                    <>
+                                        <span>·</span>
+                                        <span>v{skill.version}</span>
+                                    </>
+                                ) : null}
                             </div>
                         </div>
                     </div>
                 </div>
             </div>
-            {skill?.description ? <div className="mt-3 line-clamp-2 text-xs leading-5" style={{ color: theme.node.muted }}>{skill.description}</div> : null}
+            {skill?.description ? (
+                <div className="mt-3 line-clamp-2 text-xs leading-5" style={{ color: theme.node.muted }}>
+                    {skill.description}
+                </div>
+            ) : null}
             <div className="thin-scrollbar mt-3 min-h-0 flex-1 overflow-hidden rounded-[var(--r-md)] px-3 py-2 text-xs leading-5" style={{ background: theme.node.panel, color: theme.node.text }}>
                 <div className="mb-1 font-semibold opacity-55">模板</div>
                 <div className="line-clamp-4 whitespace-pre-wrap break-words">{template || "未配置技能模板"}</div>
             </div>
             <div className="mt-3 flex flex-wrap gap-1.5">
-                {tags.length ? tags.map((tag) => <span key={tag} className="rounded-[var(--r-sm)] bg-black/5 px-1.5 py-0.5 text-[var(--fs-tiny)] dark:bg-white/6" style={{ color: theme.node.muted }}>{tag}</span>) : <span className="text-[var(--fs-label)]" style={{ color: theme.node.muted }}>连接到图片、视频、音频或文本节点后生效</span>}
+                {tags.length ? (
+                    tags.map((tag) => (
+                        <span key={tag} className="rounded-[var(--r-sm)] bg-black/5 px-1.5 py-0.5 text-[var(--fs-tiny)] dark:bg-white/6" style={{ color: theme.node.muted }}>
+                            {tag}
+                        </span>
+                    ))
+                ) : (
+                    <span className="text-[var(--fs-label)]" style={{ color: theme.node.muted }}>
+                        连接到图片、视频、音频或文本节点后生效
+                    </span>
+                )}
             </div>
         </div>
     );
@@ -400,31 +487,69 @@ function skillOutputModeLabel(mode?: string) {
 
 function ImageNodeContent(props: CanvasNodeContentProps) {
     if (!props.node.metadata?.content && props.isBatchRoot) {
-        const content = props.node.metadata?.status === "loading"
-            ? <LoadingContent node={props.node} theme={props.theme} />
-            : props.node.metadata?.status === "error"
-                ? <ErrorContent node={props.node} theme={props.theme} onRetry={props.onRetry} onReloadResource={props.onReloadResource} />
-                : <EmptyImageContent {...props} isBatchRoot={false} />;
-        return <BatchFrame batchPreviewNodes={props.batchPreviewNodes} batchCount={props.batchCount} batchExpanded={props.batchExpanded} batchOpening={props.batchOpening} batchRecovering={props.batchRecovering} theme={props.theme} onToggleBatch={props.onToggleBatch}>{content}</BatchFrame>;
+        const content =
+            props.node.metadata?.status === "loading" ? (
+                <LoadingContent node={props.node} theme={props.theme} />
+            ) : props.node.metadata?.status === "error" ? (
+                <ErrorContent node={props.node} theme={props.theme} onRetry={props.onRetry} onReloadResource={props.onReloadResource} />
+            ) : (
+                <EmptyImageContent {...props} isBatchRoot={false} />
+            );
+        return (
+            <BatchFrame
+                batchPreviewNodes={props.batchPreviewNodes}
+                batchCount={props.batchCount}
+                batchExpanded={props.batchExpanded}
+                batchOpening={props.batchOpening}
+                batchRecovering={props.batchRecovering}
+                theme={props.theme}
+                onToggleBatch={props.onToggleBatch}
+            >
+                {content}
+            </BatchFrame>
+        );
     }
     if (!props.node.metadata?.content) return <EmptyImageContent {...props} />;
-    return <ImageContent batchPreviewNodes={props.batchPreviewNodes} node={props.node} theme={props.theme} isBatchRoot={props.isBatchRoot} batchCount={props.batchCount} batchExpanded={props.batchExpanded} batchOpening={props.batchOpening} batchRecovering={props.batchRecovering} onToggleBatch={props.onToggleBatch} />;
+    return (
+        <ImageContent
+            batchPreviewNodes={props.batchPreviewNodes}
+            node={props.node}
+            theme={props.theme}
+            isBatchRoot={props.isBatchRoot}
+            batchCount={props.batchCount}
+            batchExpanded={props.batchExpanded}
+            batchOpening={props.batchOpening}
+            batchRecovering={props.batchRecovering}
+            onToggleBatch={props.onToggleBatch}
+        />
+    );
 }
 
 function EmptyImageContent({ node, theme, isBatchRoot, batchCount, batchPreviewNodes, batchExpanded, batchOpening, batchRecovering, onToggleBatch }: CanvasNodeContentProps) {
     const isCharacterReference = node.metadata?.workflowKind === "character" && node.metadata?.characterView === "multi";
     const content = (
         <div className="flex h-full w-full flex-col items-center justify-center gap-3" style={{ color: theme.node.placeholder }}>
-            <div className="flex size-14 items-center justify-center rounded-[var(--r-lg)]" style={{ background: theme.toolbar.activeBg }}><ImageIcon className="size-6 opacity-30" /></div>
+            <div className="flex size-14 items-center justify-center rounded-[var(--r-lg)]" style={{ background: theme.toolbar.activeBg }}>
+                <ImageIcon className="size-6 opacity-30" />
+            </div>
             {isCharacterReference ? (
                 <div className="max-w-[80%] text-center">
-                    <div className="truncate text-xs font-medium" title={node.metadata?.characterName || node.title} style={{ color: theme.node.muted }}>{node.metadata?.characterName || node.title}</div>
+                    <div className="truncate text-xs font-medium" title={node.metadata?.characterName || node.title} style={{ color: theme.node.muted }}>
+                        {node.metadata?.characterName || node.title}
+                    </div>
                     <div className="mt-1 text-[var(--fs-tiny)] tracking-[0.12em] opacity-50">多视角参考 · 待生成</div>
                 </div>
-            ) : <span className="text-[var(--fs-tiny)] tracking-[0.18em] opacity-50">空图片节点</span>}
+            ) : (
+                <span className="text-[var(--fs-tiny)] tracking-[0.18em] opacity-50">空图片节点</span>
+            )}
         </div>
     );
-    if (isBatchRoot) return <BatchFrame batchPreviewNodes={batchPreviewNodes} batchCount={batchCount} batchExpanded={batchExpanded} batchOpening={batchOpening} batchRecovering={batchRecovering} theme={theme} onToggleBatch={onToggleBatch}>{content}</BatchFrame>;
+    if (isBatchRoot)
+        return (
+            <BatchFrame batchPreviewNodes={batchPreviewNodes} batchCount={batchCount} batchExpanded={batchExpanded} batchOpening={batchOpening} batchRecovering={batchRecovering} theme={theme} onToggleBatch={onToggleBatch}>
+                {content}
+            </BatchFrame>
+        );
     return content;
 }
 
@@ -432,10 +557,16 @@ function VideoNodeContent({ node, theme, mediaActive = false, onMediaPlayRequest
     const playerBoxRef = useRef<HTMLDivElement>(null);
     const { updateMediaNode } = useCanvasNodeActions();
     const { url, loading } = useVideoPlaybackUrl(node, mediaActive);
+    const preview = canvasNodeVideoPreviewReference(node);
     const subtitleEntries = node.metadata?.subtitleEntries || [];
     const subtitleStyle = node.metadata?.subtitleStyle || createDefaultSubtitleStyle();
     const [currentTimeMs, setCurrentTimeMs] = useState(0);
     const [videoSize, setVideoSize] = useState<{ width: number; height: number } | null>(null);
+    const [videoReady, setVideoReady] = useState(false);
+
+    useEffect(() => {
+        setVideoReady(false);
+    }, [url]);
 
     useEffect(() => {
         const box = playerBoxRef.current;
@@ -461,7 +592,6 @@ function VideoNodeContent({ node, theme, mediaActive = false, onMediaPlayRequest
 
     if (!node.metadata?.content && !node.metadata?.storageKey) return <EmptyMediaContent icon={<Video className="size-7 opacity-35" />} label="空视频节点" color={theme.node.placeholder} />;
     if (!mediaActive) return <InactiveVideoPreview node={node} theme={theme} onPlay={() => onMediaPlayRequest?.(node.id)} />;
-    if (!url) return <MediaLoadingState icon={<LoaderCircle className="size-5 animate-spin" />} label={loading ? "正在加载视频" : "视频资源不可用"} />;
 
     const sourceRatio = (videoSize?.width || node.metadata?.naturalWidth || node.width) / Math.max(1, videoSize?.height || node.metadata?.naturalHeight || node.height);
     const fitHeight = Math.min(node.height, node.width / Math.max(0.01, sourceRatio));
@@ -471,10 +601,38 @@ function VideoNodeContent({ node, theme, mediaActive = false, onMediaPlayRequest
 
     return (
         <div ref={playerBoxRef} className="relative flex h-full w-full items-center justify-center overflow-hidden rounded-[var(--node-radius)] bg-black">
-            <div className="relative" style={{ width: fitWidth, height: Math.round(fitHeight) }}>
-                <VideoPlayer src={url} mimeType={node.metadata?.mimeType} title={node.title || "视频"} hasAudio={inferVideoHasAudio(node.metadata)} autoPlay preload="metadata" brandColor={theme.accent.primary} className="h-full w-full rounded-[var(--node-radius)] bg-black" dataCanvasNoZoom compactControls onPlay={() => scheduleResourceBlobCache(node.metadata?.storageKey || "")} />
-                {activeEntry && activeEntry.text.trim() ? <CanvasSubtitleOverlay text={activeEntry.text} highlight={activeHighlight} style={subtitleStyle} /> : null}
-            </div>
+            {preview ? (
+                <CanvasVideoPreviewImage
+                    node={node}
+                    alt={`${node.title || "视频"} 静态预览`}
+                    loading="eager"
+                    decoding="async"
+                    draggable={false}
+                    className={`absolute inset-0 size-full select-none object-contain transition-opacity duration-150 ${videoReady ? "opacity-0" : "opacity-100"}`}
+                    loadingFallback={<LoaderCircle className="size-5 animate-spin text-white/55" />}
+                    fallback={<Video className="size-7 text-white/40" />}
+                />
+            ) : !url || loading ? (
+                <MediaLoadingState icon={<LoaderCircle className="size-5 animate-spin" />} label={loading ? "正在加载视频" : "视频资源不可用"} />
+            ) : null}
+            {url ? (
+                <div className={`relative z-[1] transition-opacity duration-150 ${videoReady ? "opacity-100" : "opacity-0"}`} style={{ width: fitWidth, height: Math.round(fitHeight) }}>
+                    <VideoPlayer
+                        src={url}
+                        mimeType={node.metadata?.mimeType}
+                        title={node.title || "视频"}
+                        hasAudio={inferVideoHasAudio(node.metadata)}
+                        autoPlay
+                        preload="metadata"
+                        brandColor={theme.accent.primary}
+                        className="h-full w-full rounded-[var(--node-radius)] bg-black"
+                        dataCanvasNoZoom
+                        compactControls
+                        onCanPlay={() => setVideoReady(true)}
+                    />
+                    {activeEntry && activeEntry.text.trim() ? <CanvasSubtitleOverlay text={activeEntry.text} highlight={activeHighlight} style={subtitleStyle} /> : null}
+                </div>
+            ) : null}
         </div>
     );
 }
@@ -507,8 +665,6 @@ function InactiveVideoPreview({ node, theme, onPlay }: Pick<CanvasNodeContentPro
     const [hydrating, setHydrating] = useState(false);
     const [localPreviewUrl, setLocalPreviewUrl] = useState("");
     const localPreviewUrlRef = useRef("");
-    const [passiveVideoUrl, setPassiveVideoUrl] = useState("");
-    const [passiveVideoReady, setPassiveVideoReady] = useState(false);
 
     useEffect(() => {
         const element = previewRef.current;
@@ -522,33 +678,12 @@ function InactiveVideoPreview({ node, theme, onPlay }: Pick<CanvasNodeContentPro
         updateMetadataRef.current = updateMetadata;
     }, [updateMetadata]);
 
-    useEffect(() => () => {
-        if (localPreviewUrlRef.current) URL.revokeObjectURL(localPreviewUrlRef.current);
-    }, []);
-
-    useEffect(() => {
-        if (hasPersistedPreview || localPreviewUrl || !nearViewport || (!node.metadata?.content && !node.metadata?.storageKey)) {
-            setPassiveVideoUrl("");
-            setPassiveVideoReady(false);
-            return;
-        }
-        let cancelled = false;
-        const content = node.metadata?.content || "";
-        const fallback = node.metadata?.importSource?.provider === "libtv" ? buildLibTVVideoSourceUrl(content) : content;
-        setPassiveVideoUrl("");
-        setPassiveVideoReady(false);
-        // This is a real <video> fallback rather than canvas extraction. It can
-        // paint the first decoded frame even when OSS allows media playback but
-        // does not expose the CORS headers required by drawImage/toBlob.
-        void resolveMediaUrl(node.metadata?.storageKey, fallback)
-            .then((url) => {
-                if (!cancelled) setPassiveVideoUrl(url);
-            })
-            .catch(() => undefined);
-        return () => {
-            cancelled = true;
-        };
-    }, [hasPersistedPreview, localPreviewUrl, nearViewport, node.metadata?.content, node.metadata?.storageKey, node.metadata?.importSource?.provider]);
+    useEffect(
+        () => () => {
+            if (localPreviewUrlRef.current) URL.revokeObjectURL(localPreviewUrlRef.current);
+        },
+        [],
+    );
 
     useEffect(() => {
         if (hasPersistedPreview || !nearViewport || (!node.metadata?.content && !node.metadata?.storageKey) || !updateMetadataRef.current) {
@@ -589,73 +724,52 @@ function InactiveVideoPreview({ node, theme, onPlay }: Pick<CanvasNodeContentPro
         };
     }, [hasPersistedPreview, nearViewport, node.id, node.metadata?.content, node.metadata?.storageKey, persistedPreviewSource, persistedPreviewStorageKey]);
 
-    if (hasPersistedPreview || localPreviewUrl || passiveVideoUrl) {
-        return <div ref={previewRef} className="group/video-preview relative size-full overflow-hidden rounded-[var(--node-radius)] bg-black">
-            {hasPersistedPreview ? (
-                <CanvasVideoPreviewImage
-                    node={node}
-                    alt={`${node.title || "视频"} 静态预览`}
-                    loading="lazy"
-                    decoding="async"
-                    draggable={false}
-                    className="pointer-events-none size-full select-none object-contain"
-                    loadingFallback={<LoaderCircle className="size-5 animate-spin text-white/55" />}
-                    fallback={<Video className="size-7 text-white/40" />}
-                />
-            ) : localPreviewUrl ? (
-                <img src={localPreviewUrl} alt={`${node.title || "视频"} 静态预览`} loading="lazy" decoding="async" draggable={false} className="pointer-events-none size-full select-none object-contain" />
-            ) : (
-                <>
-                    <video
-                        src={passiveVideoUrl}
-                        aria-hidden="true"
-                        tabIndex={-1}
-                        muted
-                        playsInline
-                        preload="auto"
+    if (hasPersistedPreview || localPreviewUrl) {
+        return (
+            <div ref={previewRef} className="group/video-preview relative size-full overflow-hidden rounded-[var(--node-radius)] bg-black">
+                {hasPersistedPreview ? (
+                    <CanvasVideoPreviewImage
+                        node={node}
+                        alt={`${node.title || "视频"} 静态预览`}
+                        loading="lazy"
+                        decoding="async"
                         draggable={false}
-                        className={`pointer-events-none size-full select-none object-contain transition-opacity ${passiveVideoReady ? "opacity-100" : "opacity-0"}`}
-                        onLoadedMetadata={(event) => {
-                            const video = event.currentTarget;
-                            if (video.readyState >= 2) {
-                                setPassiveVideoReady(true);
-                                return;
-                            }
-                            // Some browsers stop at metadata when the element is muted and
-                            // offscreen. A tiny seek forces an actual frame decode without
-                            // starting playback or requiring canvas/CORS access.
-                            if (Number.isFinite(video.duration) && video.duration > 0) {
-                                try {
-                                    video.currentTime = Math.min(0.001, video.duration / 2);
-                                } catch {
-                                    // loadeddata/canplay will still reveal the frame if seeking is unavailable.
-                                }
-                            }
-                        }}
-                        onLoadedData={() => setPassiveVideoReady(true)}
-                        onCanPlay={() => setPassiveVideoReady(true)}
-                        onSeeked={(event) => {
-                            if (event.currentTarget.readyState >= 2) setPassiveVideoReady(true);
-                        }}
-                        onError={() => {
-                            setPassiveVideoReady(false);
-                            setPassiveVideoUrl("");
-                        }}
+                        className="pointer-events-none size-full select-none object-contain"
+                        loadingFallback={<LoaderCircle className="size-5 animate-spin text-white/55" />}
+                        fallback={<Video className="size-7 text-white/40" />}
                     />
-                    {!passiveVideoReady ? <div className="absolute inset-0"><InactiveMediaCard icon={<Video className="size-7" />} title={node.title || "视频"} hint={hydrating ? "正在生成首帧" : "正在读取首帧"} theme={theme} /></div> : null}
-                </>
-            )}
-            <VideoPreviewPlayButton title={node.title || "视频"} onPlay={onPlay} />
-        </div>;
+                ) : (
+                    <img src={localPreviewUrl} alt={`${node.title || "视频"} 静态预览`} loading="lazy" decoding="async" draggable={false} className="pointer-events-none size-full select-none object-contain" />
+                )}
+                <VideoPreviewPlayButton title={node.title || "视频"} onPlay={onPlay} />
+            </div>
+        );
     }
-    return <div ref={previewRef} className="group/video-preview relative size-full">
-        <InactiveMediaCard icon={<Video className="size-7" />} title={node.title || "视频"} hint={hydrating ? "正在生成首帧" : nearViewport ? "点击播放视频" : "进入视口后加载首帧"} theme={theme} />
-        <VideoPreviewPlayButton title={node.title || "视频"} onPlay={onPlay} />
-    </div>;
+    return (
+        <div ref={previewRef} className="group/video-preview relative size-full">
+            <InactiveMediaCard icon={<Video className="size-7" />} title={node.title || "视频"} hint={hydrating ? "正在生成首帧" : nearViewport ? "点击播放视频" : "进入视口后加载首帧"} theme={theme} />
+            <VideoPreviewPlayButton title={node.title || "视频"} onPlay={onPlay} />
+        </div>
+    );
 }
 
 function VideoPreviewPlayButton({ title, onPlay }: { title: string; onPlay: () => void }) {
-    return <button type="button" className="absolute left-1/2 top-1/2 z-[var(--node-z-overlay)] grid size-11 -translate-x-1/2 -translate-y-1/2 place-items-center rounded-full bg-black/62 text-white shadow-lg backdrop-blur transition-[transform,background-color,opacity] hover:scale-105 hover:bg-black/78 focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-white" aria-label={`播放 ${title}`} title="播放视频" onPointerDown={(event) => event.stopPropagation()} onMouseDown={(event) => event.stopPropagation()} onClick={(event) => { event.stopPropagation(); onPlay(); }}><Play className="ml-0.5 size-5 fill-current" /></button>;
+    return (
+        <button
+            type="button"
+            className="absolute left-1/2 top-1/2 z-[var(--node-z-overlay)] grid size-11 -translate-x-1/2 -translate-y-1/2 place-items-center rounded-full bg-black/62 text-white shadow-lg backdrop-blur transition-[transform,background-color,opacity] hover:scale-105 hover:bg-black/78 focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-white"
+            aria-label={`播放 ${title}`}
+            title="播放视频"
+            onPointerDown={(event) => event.stopPropagation()}
+            onMouseDown={(event) => event.stopPropagation()}
+            onClick={(event) => {
+                event.stopPropagation();
+                onPlay();
+            }}
+        >
+            <Play className="ml-0.5 size-5 fill-current" />
+        </button>
+    );
 }
 
 function useVideoPlaybackUrl(node: CanvasNodeData, active: boolean) {
@@ -674,28 +788,64 @@ function useVideoPlaybackUrl(node: CanvasNodeData, active: boolean) {
         }
         setLoading(true);
         void resolveMediaUrl(storageKey, fallback)
-            .then((resolved) => { if (!cancelled) setUrl(resolved); })
-            .catch(() => { if (!cancelled) setUrl(fallback); })
-            .finally(() => { if (!cancelled) setLoading(false); });
-        return () => { cancelled = true; };
+            .then((resolved) => {
+                if (!cancelled) setUrl(resolved);
+            })
+            .catch(() => {
+                if (!cancelled) setUrl(fallback);
+            })
+            .finally(() => {
+                if (!cancelled) setLoading(false);
+            });
+        return () => {
+            cancelled = true;
+        };
     }, [active, fallback, storageKey]);
 
     return { url, loading };
 }
 
 function InactiveMediaCard({ icon, title, hint, theme }: { icon: ReactNode; title: string; hint: string; theme: CanvasTheme }) {
-    return <div className="flex size-full flex-col items-center justify-center gap-2 rounded-[var(--node-radius)] px-4 text-center" style={{ background: theme.node.fill, color: theme.node.muted }}><span className="opacity-40">{icon}</span><span className="max-w-full truncate text-xs font-medium" title={title}>{title}</span><span className="text-[var(--fs-tiny)] opacity-50">{hint}</span></div>;
+    return (
+        <div className="flex size-full flex-col items-center justify-center gap-2 rounded-[var(--node-radius)] px-4 text-center" style={{ background: theme.node.fill, color: theme.node.muted }}>
+            <span className="opacity-40">{icon}</span>
+            <span className="max-w-full truncate text-xs font-medium" title={title}>
+                {title}
+            </span>
+            <span className="text-[var(--fs-tiny)] opacity-50">{hint}</span>
+        </div>
+    );
 }
 
 function MediaLoadingState({ icon, label }: { icon: ReactNode; label: string }) {
-    return <div role="status" className="flex size-full flex-col items-center justify-center gap-2 rounded-[var(--node-radius)] bg-black text-white/75"><span className="grid size-10 place-items-center rounded-full bg-white/10">{icon}</span><span className="text-xs font-medium">{label}</span></div>;
+    return (
+        <div role="status" className="flex size-full flex-col items-center justify-center gap-2 rounded-[var(--node-radius)] bg-black text-white/75">
+            <span className="grid size-10 place-items-center rounded-full bg-white/10">{icon}</span>
+            <span className="text-xs font-medium">{label}</span>
+        </div>
+    );
 }
 
 function EmptyMediaContent({ icon, label, color }: { icon: ReactNode; label: string; color: string }) {
-    return <div className="flex h-full w-full flex-col items-center justify-center gap-3" style={{ color }}>{icon}<span className="text-sm">{label}</span></div>;
+    return (
+        <div className="flex h-full w-full flex-col items-center justify-center gap-3" style={{ color }}>
+            {icon}
+            <span className="text-sm">{label}</span>
+        </div>
+    );
 }
 
-function ImageContent({ node, theme, isBatchRoot, batchCount, batchPreviewNodes, batchExpanded, batchOpening, batchRecovering, onToggleBatch }: Pick<CanvasNodeContentProps, "node" | "theme" | "isBatchRoot" | "batchCount" | "batchPreviewNodes" | "batchExpanded" | "batchOpening" | "batchRecovering" | "onToggleBatch">) {
+function ImageContent({
+    node,
+    theme,
+    isBatchRoot,
+    batchCount,
+    batchPreviewNodes,
+    batchExpanded,
+    batchOpening,
+    batchRecovering,
+    onToggleBatch,
+}: Pick<CanvasNodeContentProps, "node" | "theme" | "isBatchRoot" | "batchCount" | "batchPreviewNodes" | "batchExpanded" | "batchOpening" | "batchRecovering" | "onToggleBatch">) {
     const imageContainerRef = useRef<HTMLDivElement>(null);
     const nearViewport = useNearViewport(imageContainerRef);
     const { url, loading } = useNodeResourceUrl(node, nearViewport);
@@ -741,7 +891,22 @@ function ImageContent({ node, theme, isBatchRoot, batchCount, batchPreviewNodes,
     return (
         <BatchFrame batchPreviewNodes={batchPreviewNodes} batchCount={isBatchRoot ? batchCount : 0} batchExpanded={batchExpanded} batchOpening={batchOpening} batchRecovering={batchRecovering} theme={theme} onToggleBatch={onToggleBatch}>
             <div ref={imageContainerRef} className="h-full w-full overflow-hidden rounded-[var(--node-radius)]">
-                {url ? <img src={url} alt={node.title} loading="lazy" decoding="async" draggable={false} onDragStart={(event) => event.preventDefault()} onLoad={(event) => fitToImage(event.currentTarget)} className={`pointer-events-none block h-full w-full select-none ${node.metadata?.freeResize ? "object-fill" : "object-contain"}`} /> : <div className="grid size-full place-items-center" style={{ color: theme.node.muted }}>{loading ? <LoaderCircle className="size-5 animate-spin" /> : <ImageIcon className="size-5 opacity-45" />}</div>}
+                {url ? (
+                    <img
+                        src={url}
+                        alt={node.title}
+                        loading="lazy"
+                        decoding="async"
+                        draggable={false}
+                        onDragStart={(event) => event.preventDefault()}
+                        onLoad={(event) => fitToImage(event.currentTarget)}
+                        className={`pointer-events-none block h-full w-full select-none ${node.metadata?.freeResize ? "object-fill" : "object-contain"}`}
+                    />
+                ) : (
+                    <div className="grid size-full place-items-center" style={{ color: theme.node.muted }}>
+                        {loading ? <LoaderCircle className="size-5 animate-spin" /> : <ImageIcon className="size-5 opacity-45" />}
+                    </div>
+                )}
             </div>
         </BatchFrame>
     );
@@ -750,23 +915,21 @@ function ImageContent({ node, theme, isBatchRoot, batchCount, batchPreviewNodes,
 function useNodeResourceUrl(node: CanvasNodeData, eager: boolean) {
     const storageKey = node.metadata?.storageKey || "";
     const rawContent = node.metadata?.content || "";
-    const content = node.type === CanvasNodeType.Video && node.metadata?.importSource?.provider === "libtv"
-        ? buildLibTVVideoSourceUrl(rawContent)
-        : rawContent;
+    const content = node.type === CanvasNodeType.Video && node.metadata?.importSource?.provider === "libtv" ? buildLibTVVideoSourceUrl(rawContent) : rawContent;
     // `previewContent` is intentionally passive-only.  When a media node is
     // activated, VideoPlayer/Audio must receive the playable asset, never the
     // LibTV OSS snapshot URL stored for the thumbnail.
-    const fallback = node.type === CanvasNodeType.Video || node.type === CanvasNodeType.Audio
-        ? content
-        : node.metadata?.previewContent
-            || (node.type === CanvasNodeType.Image && node.metadata?.importSource?.provider === "libtv" ? buildLibTVImagePreviewUrl(content) : content);
+    const fallback =
+        node.type === CanvasNodeType.Video || node.type === CanvasNodeType.Audio
+            ? content
+            : node.metadata?.previewContent || (node.type === CanvasNodeType.Image && node.metadata?.importSource?.provider === "libtv" ? buildLibTVImagePreviewUrl(content) : content);
     const isRemoteResource = storageKey.startsWith("resource:");
     // Inline data URLs are already local, but decoding thousands of them is
     // still expensive. Images must wait for the same viewport gate as remote
     // resources; otherwise DOM virtualization does not reduce image work.
     const isLazyVisual = node.type === CanvasNodeType.Image;
     const isHttpUrl = Boolean(fallback && !fallback.startsWith("data:"));
-    const initialUrl = eager && !isRemoteResource && isLazyVisual && isHttpUrl ? fallback : (isRemoteResource || isLazyVisual ? "" : fallback);
+    const initialUrl = eager && !isRemoteResource && isLazyVisual && isHttpUrl ? fallback : isRemoteResource || isLazyVisual ? "" : fallback;
     const [url, setUrl] = useState(() => initialUrl);
     const [loading, setLoading] = useState(() => !initialUrl && isRemoteResource && eager);
 
@@ -810,12 +973,15 @@ function useNearViewport(ref: RefObject<Element | null>) {
             setNearViewport(true);
             return;
         }
-        const observer = new IntersectionObserver((entries) => {
-            if (entries.some((entry) => entry.isIntersecting)) {
-                setNearViewport(true);
-                observer.disconnect();
-            }
-        }, { rootMargin: "600px" });
+        const observer = new IntersectionObserver(
+            (entries) => {
+                if (entries.some((entry) => entry.isIntersecting)) {
+                    setNearViewport(true);
+                    observer.disconnect();
+                }
+            },
+            { rootMargin: "600px" },
+        );
         observer.observe(element);
         return () => observer.disconnect();
     }, [ref]);
@@ -826,20 +992,57 @@ export function CanvasNodeImageInfo({ node }: { node: CanvasNodeData }) {
     const width = Math.round(node.metadata?.naturalWidth || node.width);
     const height = Math.round(node.metadata?.naturalHeight || node.height);
     const size = formatBytes(node.metadata?.bytes || 0);
-    return <span className="ml-auto max-w-full shrink-0 truncate rounded-[var(--r-sm)] bg-black/55 px-2 py-1 text-[var(--fs-label)] font-medium leading-none text-white backdrop-blur-sm">{width} x {height}{size ? ` · ${size}` : ""}</span>;
+    return (
+        <span className="ml-auto max-w-full shrink-0 truncate rounded-[var(--r-sm)] bg-black/55 px-2 py-1 text-[var(--fs-label)] font-medium leading-none text-white backdrop-blur-sm">
+            {width} x {height}
+            {size ? ` · ${size}` : ""}
+        </span>
+    );
 }
 
 function BatchPreviewImage({ node }: { node: CanvasNodeData }) {
     const ref = useRef<HTMLDivElement>(null);
     const nearViewport = useNearViewport(ref);
     const { url } = useNodeResourceUrl(node, nearViewport);
-    return <div ref={ref} className="h-full w-full overflow-hidden rounded-[inherit]">{url ? <img src={url} alt={`子图预览：${node.title}`} className="h-full w-full object-contain" draggable={false} /> : null}</div>;
+    return (
+        <div ref={ref} className="h-full w-full overflow-hidden rounded-[inherit]">
+            {url ? <img src={url} alt={`子图预览：${node.title}`} className="h-full w-full object-contain" draggable={false} /> : null}
+        </div>
+    );
 }
 
-function BatchFrame({ batchCount, batchPreviewNodes, batchExpanded, batchOpening, batchRecovering, theme, onToggleBatch, children }: { batchCount: number; batchPreviewNodes?: CanvasNodeData[]; batchExpanded: boolean; batchOpening: boolean; batchRecovering: boolean; theme: CanvasTheme; onToggleBatch?: () => void; children: ReactNode }) {
+function BatchFrame({
+    batchCount,
+    batchPreviewNodes,
+    batchExpanded,
+    batchOpening,
+    batchRecovering,
+    theme,
+    onToggleBatch,
+    children,
+}: {
+    batchCount: number;
+    batchPreviewNodes?: CanvasNodeData[];
+    batchExpanded: boolean;
+    batchOpening: boolean;
+    batchRecovering: boolean;
+    theme: CanvasTheme;
+    onToggleBatch?: () => void;
+    children: ReactNode;
+}) {
     const isBatchRoot = batchCount > 1;
     return (
-        <div className="group/batch relative h-full w-full overflow-visible" onDoubleClick={isBatchRoot ? (event) => { event.stopPropagation(); onToggleBatch?.(); } : undefined}>
+        <div
+            className="group/batch relative h-full w-full overflow-visible"
+            onDoubleClick={
+                isBatchRoot
+                    ? (event) => {
+                          event.stopPropagation();
+                          onToggleBatch?.();
+                      }
+                    : undefined
+            }
+        >
             {isBatchRoot ? (
                 <div className="pointer-events-none absolute inset-0 overflow-visible">
                     {Array.from({ length: Math.min(batchCount - 1, 5) }).map((_, index) => (
@@ -851,7 +1054,8 @@ function BatchFrame({ batchCount, batchPreviewNodes, batchExpanded, batchOpening
                                 background: theme.node.panel,
                                 boxShadow: `inset 0 0 0 1px ${theme.node.stroke}`,
                                 opacity: batchExpanded && !batchOpening ? 0.34 : 1,
-                                transform: batchOpening || batchRecovering ? `translate(${54 + index * 22}px, ${20 + index * 12}px) rotate(${8 + index * 5}deg) scale(.98)` : `translate(${34 + index * 18}px, ${14 + index * 10}px) rotate(${6 + index * 4}deg)`,
+                                transform:
+                                    batchOpening || batchRecovering ? `translate(${54 + index * 22}px, ${20 + index * 12}px) rotate(${8 + index * 5}deg) scale(.98)` : `translate(${34 + index * 18}px, ${14 + index * 10}px) rotate(${6 + index * 4}deg)`,
                                 zIndex: -index - 1,
                             }}
                         >
diff --git a/web/src/components/canvas/canvas-node.tsx b/web/src/components/canvas/canvas-node.tsx
index 48b9bdd18..07609729b 100644
--- a/web/src/components/canvas/canvas-node.tsx
+++ b/web/src/components/canvas/canvas-node.tsx
@@ -5,6 +5,7 @@ import { AlertCircle, BookOpenCheck, CheckCircle2, ChevronRight, Clapperboard, C
 import { useCanvasNodeActions } from "./canvas-node-action-context";
 
 import { canvasThemes } from "@/lib/canvas-theme";
+import type { CanvasNodeRenderLOD } from "@/lib/canvas/canvas-node-lod";
 import { canvasConnectionTilt } from "@/lib/canvas/canvas-connection-tilt";
 import { storyboardMinNodeHeight } from "@/lib/canvas/canvas-storyboard-layout";
 import { resourceStorageLabel, resourceStorageLocation, resourceStorageTitle } from "@/lib/canvas/resource-storage-status";
@@ -20,6 +21,7 @@ type CanvasTheme = (typeof canvasThemes)[keyof typeof canvasThemes];
 
 type CanvasNodeProps = {
     data: CanvasNodeData;
+    renderLOD?: CanvasNodeRenderLOD;
     dragOffset?: Position;
     scale: number;
     isSelected: boolean;
@@ -68,6 +70,7 @@ type CanvasNodeProps = {
 
 export const CanvasNode = React.memo(function CanvasNode({
     data,
+    renderLOD = "full",
     dragOffset,
     scale,
     isSelected,
@@ -128,6 +131,8 @@ export const CanvasNode = React.memo(function CanvasNode({
     const isBatchChild = data.type === CanvasNodeType.Image && Boolean(data.metadata?.batchRootId);
     const showStatusTrack = Boolean(resourceLabel || data.metadata?.locked || isBatchRoot || (isBatchChild && !readOnly) || (hasMediaContent && !readOnly));
     const isActive = isConnectionTarget || isSelected || isFocusRelated;
+    const effectiveRenderLOD: CanvasNodeRenderLOD = renderLOD === "full" || hovered || isEditingContent || isEditingTitle || mediaActive ? "full" : renderLOD;
+    const showChrome = effectiveRenderLOD === "full";
     const nodeState = isFocusRelated ? "focus" : isConnectionTarget ? "target" : isSelected ? "selected" : isRelated && !isBatchChild ? "related" : "idle";
     const showOutputConnection = getNodeDefinition(data.type)?.showOutputConnection !== false;
     const assetTags = data.metadata?.assetTags?.filter((tag) => tag.trim()) || [];
@@ -272,6 +277,7 @@ export const CanvasNode = React.memo(function CanvasNode({
     return (
         <div
             data-node-id={data.id}
+            data-node-lod={effectiveRenderLOD}
             className={`node-element absolute flex select-none flex-col ${dragOffset ? "cursor-grabbing" : data.type === CanvasNodeType.Drawing ? "cursor-pointer" : "cursor-default"} ${isSelected && data.type === CanvasNodeType.Video ? "z-[var(--z-node-toolbar)]" : isSelected || isFocusRelated || isConnectionTarget ? "z-[var(--z-node-active)]" : "z-[var(--z-node)]"}`}
             style={{
                 transform: `translate(${data.position.x + (dragOffset?.x || 0)}px, ${data.position.y + (dragOffset?.y || 0)}px)`,
@@ -289,7 +295,7 @@ export const CanvasNode = React.memo(function CanvasNode({
             }}
             onContextMenu={(event) => onContextMenu(event, data.id)}
         >
-            <NodeExternalHeader
+            {showChrome ? <NodeExternalHeader
                 node={data}
                 scale={scale}
                 dimensionLabel={mediaDimensionLabel}
@@ -303,7 +309,7 @@ export const CanvasNode = React.memo(function CanvasNode({
                 onEdit={() => setIsEditingTitle(true)}
                 onCommit={commitTitle}
                 onCancel={() => { setTitleDraft(data.title); setIsEditingTitle(false); }}
-            />
+            /> : null}
             <div
                 className="canvas-node-shell relative h-full w-full overflow-visible rounded-[var(--node-radius)]"
                 data-node-state={nodeState}
@@ -313,7 +319,8 @@ export const CanvasNode = React.memo(function CanvasNode({
                     background: hasImageContent || hasVideoContent ? "transparent" : theme.node.fill,
                     // 固定占位但不绘制描边，避免聚焦切换时边框宽度变化造成白边跳动。
                     border: isComposerNode ? "0" : "1px solid transparent",
-                    boxShadow: isComposerNode ? "none" : isSelected || isFocusRelated ? theme.node.hoverShadow : theme.node.shadow,
+                    boxShadow: isComposerNode || !showChrome ? "none" : isSelected || isFocusRelated ? theme.node.hoverShadow : theme.node.shadow,
+                    outline: !showChrome && isActive ? `1px solid ${theme.node.activeStroke}` : undefined,
                     "--connection-tilt-x": `${connectionTilt?.rotateX || 0}deg`,
                     "--connection-tilt-y": `${connectionTilt?.rotateY || 0}deg`,
                     transformOrigin: connectionTilt?.origin,
@@ -364,12 +371,13 @@ export const CanvasNode = React.memo(function CanvasNode({
                     }
                 >
                     {/* 节点状态徽章（对应 #97 决策2：左上角 loading/success/error，近距离确认信号）*/}
-                    {data.metadata?.status && data.metadata.status !== "idle" && data.type !== CanvasNodeType.Frame ? (
+                    {showChrome && data.metadata?.status && data.metadata.status !== "idle" && data.type !== CanvasNodeType.Frame ? (
                         <NodeStatusBadge status={data.metadata.status} />
                     ) : null}
                     <CanvasNodeContent
                         node={data}
                         theme={theme}
+                        renderLOD={effectiveRenderLOD}
                         isEditingContent={isEditingContent}
                         textareaRef={textareaRef}
                         isBatchRoot={isBatchRoot}
@@ -393,7 +401,7 @@ export const CanvasNode = React.memo(function CanvasNode({
                     />
                 </div>
 
-                {data.type === CanvasNodeType.Text && data.metadata?.workflowKind !== "character" && !readOnly ? (
+                {showChrome && data.type === CanvasNodeType.Text && data.metadata?.workflowKind !== "character" && !readOnly ? (
                     <div
                         className={`absolute bottom-[10%] left-1/2 z-[var(--node-z-overlay)] -translate-x-1/2 motion-safe:transition motion-safe:duration-200 ${isSelected ? "translate-y-0 opacity-100" : "pointer-events-none translate-y-3 opacity-0"}`}
                         onMouseDown={(event) => event.stopPropagation()}
@@ -412,7 +420,7 @@ export const CanvasNode = React.memo(function CanvasNode({
                     </div>
                 ) : null}
 
-                {data.metadata?.versionLabel ? (
+                {showChrome && data.metadata?.versionLabel ? (
                     <button
                         type="button"
                         className="absolute left-3 top-3 z-[var(--node-z-overlay)] grid size-7 place-items-center rounded-[var(--r-full)] border p-0.5 text-[var(--node-badge-fs)] font-semibold leading-none backdrop-blur-md transition-[transform,background,border-color,box-shadow] hover:-translate-y-px focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 motion-reduce:hover:translate-y-0"
@@ -430,7 +438,7 @@ export const CanvasNode = React.memo(function CanvasNode({
                         {data.metadata.versionLabel}
                     </button>
                 ) : null}
-                {showStatusTrack ? (
+                {showChrome && showStatusTrack ? (
                     <div className={`absolute right-3 top-3 z-[var(--node-z-overlay)] flex min-w-0 items-center justify-end gap-1 ${data.metadata?.versionLabel ? "max-w-[calc(100%-104px)]" : "max-w-[calc(100%-24px)]"}`}>
                         {resourceLabel && data.type !== CanvasNodeType.Image ? <ResourceLabelBadge reference={resourceLabel} theme={theme} /> : null}
                         {hasMediaContent && !readOnly ? <ResourceStorageBadge storageKey={data.metadata?.storageKey} active={isActive} theme={theme} /> : null}
@@ -440,7 +448,7 @@ export const CanvasNode = React.memo(function CanvasNode({
                     </div>
                 ) : null}
                 {/* 批次子图操作条：成功子项提供下载/副本/设为主图，失败子项提供重试/删除 */}
-                {isBatchChild && !readOnly && (hasImageContent || data.metadata?.status === "error") && (hovered || isSelected) ? (
+                {showChrome && isBatchChild && !readOnly && (hasImageContent || data.metadata?.status === "error") && (hovered || isSelected) ? (
                     <div
                         className="absolute inset-x-0 bottom-2 z-[var(--node-z-overlay)] flex justify-center"
                         onMouseDown={(event) => event.stopPropagation()}
@@ -459,19 +467,19 @@ export const CanvasNode = React.memo(function CanvasNode({
                     </div>
                 ) : null}
                 {/* 批次主图位（折叠根节点封面）常驻下载按钮 */}
-                {isBatchRoot && hasImageContent && !readOnly ? (
+                {showChrome && isBatchRoot && hasImageContent && !readOnly ? (
                     <div className="absolute bottom-2 right-2 z-[var(--node-z-overlay)]" onMouseDown={(event) => event.stopPropagation()} onPointerDown={(event) => event.stopPropagation()}>
                         <BatchChildActionButton theme={theme} label="下载主图" icon={<Download className="size-3.5" />} onClick={() => downloadNode?.(data)} />
                     </div>
                 ) : null}
-                {assetTags.length || (showImageInfo && hasImageContent) ? (
+                {showChrome && (assetTags.length || (showImageInfo && hasImageContent)) ? (
                     <div className="pointer-events-none absolute inset-x-3 bottom-3 z-[var(--node-z-overlay)] flex items-end justify-between gap-2">
                         {assetTags.length ? <AssetTagBadges tags={assetTags} theme={theme} /> : null}
                         {showImageInfo && hasImageContent ? <CanvasNodeImageInfo node={data} /> : null}
                     </div>
                 ) : null}
 
-                {!readOnly && !data.metadata?.locked && (isSelected || hovered) ? <>
+                {showChrome && !readOnly && !data.metadata?.locked && (isSelected || hovered) ? <>
                     <ResizeHandle corner="top-left" onMouseDown={handleResizeMouseDown} />
                     <ResizeHandle corner="top-right" onMouseDown={handleResizeMouseDown} />
                     <ResizeHandle corner="bottom-left" onMouseDown={handleResizeMouseDown} />
@@ -479,8 +487,8 @@ export const CanvasNode = React.memo(function CanvasNode({
                 </> : null}
             </div>
 
-            {!readOnly && data.type !== CanvasNodeType.Script && data.type !== CanvasNodeType.BatchTable ? <ConnectionSideRail side="left" scale={scale} theme={theme} visible={hovered || forceInputVisible} onPointerDown={(event, anchorRatio) => onConnectStart(event, data.id, "target", undefined, anchorRatio)} /> : null}
-            {!readOnly && data.type !== CanvasNodeType.Script && data.type !== CanvasNodeType.Config && showOutputConnection ? <ConnectionSideRail side="right" scale={scale} theme={theme} visible={hovered} onPointerDown={(event, anchorRatio) => onConnectStart(event, data.id, "source", undefined, anchorRatio)} /> : null}
+            {(showChrome || forceInputVisible) && !readOnly && data.type !== CanvasNodeType.Script && data.type !== CanvasNodeType.BatchTable ? <ConnectionSideRail side="left" scale={scale} theme={theme} visible={hovered || forceInputVisible} onPointerDown={(event, anchorRatio) => onConnectStart(event, data.id, "target", undefined, anchorRatio)} /> : null}
+            {showChrome && !readOnly && data.type !== CanvasNodeType.Script && data.type !== CanvasNodeType.Config && showOutputConnection ? <ConnectionSideRail side="right" scale={scale} theme={theme} visible={hovered} onPointerDown={(event, anchorRatio) => onConnectStart(event, data.id, "source", undefined, anchorRatio)} /> : null}
 
         </div>
     );
@@ -489,6 +497,7 @@ export const CanvasNode = React.memo(function CanvasNode({
 function areCanvasNodePropsEqual(previous: CanvasNodeProps, next: CanvasNodeProps) {
     return (
         previous.data === next.data &&
+        previous.renderLOD === next.renderLOD &&
         previous.dragOffset?.x === next.dragOffset?.x &&
         previous.dragOffset?.y === next.dragOffset?.y &&
         previous.scale === next.scale &&
diff --git a/web/src/components/canvas/infinite-canvas.tsx b/web/src/components/canvas/infinite-canvas.tsx
index 74c5cf342..7171a1bb5 100644
--- a/web/src/components/canvas/infinite-canvas.tsx
+++ b/web/src/components/canvas/infinite-canvas.tsx
@@ -128,8 +128,7 @@ export function InfiniteCanvas({ interactive = true, containerRef, viewport, app
             const container = containerRef.current;
             if (container) container.dataset.canvasViewportInteracting = "true";
             nextViewportRef.current = next;
-            if (frameRef.current) return;
-            frameRef.current = requestAnimationFrame((now) => {
+            if (!frameRef.current) frameRef.current = requestAnimationFrame((now) => {
                 frameRef.current = null;
                 const pending = nextViewportRef.current;
                 if (!pending) return;
diff --git a/web/src/lib/canvas/canvas-content.ts b/web/src/lib/canvas/canvas-content.ts
index 07789471e..852d032ba 100644
--- a/web/src/lib/canvas/canvas-content.ts
+++ b/web/src/lib/canvas/canvas-content.ts
@@ -15,8 +15,30 @@ export function sameCanvasContent(left: CanvasProject | undefined, right: Canvas
     return [...new Set([...Object.keys(a), ...Object.keys(b)])].every((key) => a[key] === b[key] || canonicalize(a[key]) === canonicalize(b[key]));
 }
 
-export async function canvasContentHash(project: CanvasProject) {
-    const serialized = canonicalize(canvasContentSnapshot(project));
+type ContentSnapshot = ReturnType<typeof canvasContentSnapshot>;
+const contentHashes = new WeakMap<CanvasProject["nodes"], { content: ContentSnapshot; hash: Promise<string> }>();
+
+// Store updates are immutable. Reuse a hash across viewport/revision-only copies;
+// any content field/reference change invalidates it. Weak keys bound its lifetime.
+export function canvasContentHash(project: CanvasProject): Promise<string> {
+    const content = canvasContentSnapshot(project);
+    const cached = contentHashes.get(project.nodes);
+    if (cached && sameContentReferences(cached.content, content)) return cached.hash;
+    const hash = hashContent(content);
+    contentHashes.set(project.nodes, { content, hash });
+    void hash.catch(() => {
+        if (contentHashes.get(project.nodes)?.hash === hash) contentHashes.delete(project.nodes);
+    });
+    return hash;
+}
+
+function sameContentReferences(a: ContentSnapshot, b: ContentSnapshot) {
+    const keys = Object.keys(a) as (keyof ContentSnapshot)[];
+    return keys.length === Object.keys(b).length && keys.every((key) => a[key] === b[key]);
+}
+
+async function hashContent(content: ContentSnapshot) {
+    const serialized = canonicalize(content);
     // LAN HTTP deployments may lack Web Crypto. Keep an exact baseline there;
     // a lossy checksum could incorrectly discard an unsaved draft during login.
     if (!globalThis.crypto?.subtle) return `json:${serialized}`;
diff --git a/web/src/lib/canvas/canvas-node-lod.ts b/web/src/lib/canvas/canvas-node-lod.ts
new file mode 100644
index 000000000..7b01248d4
--- /dev/null
+++ b/web/src/lib/canvas/canvas-node-lod.ts
@@ -0,0 +1,12 @@
+export type CanvasNodeRenderLOD = "shell" | "preview" | "full";
+
+// Hysteresis prevents mounting/unmounting editors around the overview boundary.
+export function canvasOverviewMode(scale: number, previous: boolean) {
+    return previous ? scale < 0.27 : scale < 0.23;
+}
+
+export function resolveCanvasNodeLOD(overview: boolean, inView: boolean, inEntry: boolean, editing: boolean): CanvasNodeRenderLOD {
+    if (editing) return "full";
+    if (inView) return overview ? "preview" : "full";
+    return inEntry ? "preview" : "shell";
+}
diff --git a/web/src/lib/canvas/canvas-node-visibility.ts b/web/src/lib/canvas/canvas-node-visibility.ts
index 81362d901..56033387c 100644
--- a/web/src/lib/canvas/canvas-node-visibility.ts
+++ b/web/src/lib/canvas/canvas-node-visibility.ts
@@ -1,7 +1,7 @@
 import { canvasNodeBounds, type CanvasSpatialBounds, type CanvasSpatialIndex } from "@/lib/canvas/canvas-spatial-index";
 import type { CanvasNodeData } from "@/types/canvas";
 
-const intersects = (a: CanvasSpatialBounds, b: CanvasSpatialBounds) => a.right > b.left && a.left < b.right && a.bottom > b.top && a.top < b.bottom;
+export const intersectsCanvasBounds = (a: CanvasSpatialBounds, b: CanvasSpatialBounds) => a.right > b.left && a.left < b.right && a.bottom > b.top && a.top < b.bottom;
 
 /** 预算只能裁减屏外预加载，不能裁掉屏内节点或正在交互的节点。 */
 export function selectCanvasVisibleNodes({
@@ -25,8 +25,8 @@ export function selectCanvasVisibleNodes({
         const node = nodeById.get(id);
         if (!node || hiddenIds.has(id)) continue;
         const bounds = canvasNodeBounds(node);
-        if (forcedIds.has(id) || intersects(bounds, view)) visible.push(node);
-        else if (retainedIds.has(id) || intersects(bounds, enter)) overscan.push(node);
+        if (forcedIds.has(id) || intersectsCanvasBounds(bounds, view)) visible.push(node);
+        else if (retainedIds.has(id) || intersectsCanvasBounds(bounds, enter)) overscan.push(node);
     }
     return [...visible, ...overscan.slice(0, Math.max(0, budget - visible.length))];
 }
diff --git a/web/src/lib/canvas/task-ticker.ts b/web/src/lib/canvas/task-ticker.ts
new file mode 100644
index 000000000..f0d889a4d
--- /dev/null
+++ b/web/src/lib/canvas/task-ticker.ts
@@ -0,0 +1,37 @@
+// One clock per canvas runtime, not one timer per loading node. No work while
+// hidden or when the final loading node unmounts.
+const listeners = new Set<() => void>();
+let now = Date.now();
+let timer: ReturnType<typeof setInterval> | undefined;
+
+export const taskTickerSnapshot = () => now;
+export const idleTaskTickerSubscribe = () => () => {};
+
+function tick() {
+    now = Date.now();
+    for (const listener of listeners) listener();
+}
+
+function reconcileTimer() {
+    if (timer !== undefined) clearInterval(timer);
+    timer = undefined;
+    if (listeners.size && (typeof document === "undefined" || !document.hidden)) {
+        tick();
+        timer = setInterval(tick, 1000);
+    }
+}
+
+export function subscribeTaskTicker(listener: () => void) {
+    listeners.add(listener);
+    if (listeners.size === 1) {
+        if (typeof document !== "undefined") document.addEventListener("visibilitychange", reconcileTimer);
+        reconcileTimer();
+    }
+    return () => {
+        listeners.delete(listener);
+        if (!listeners.size) {
+            if (typeof document !== "undefined") document.removeEventListener("visibilitychange", reconcileTimer);
+            reconcileTimer();
+        }
+    };
+}
diff --git a/web/src/pages/canvas/canvas-project-world-layers.tsx b/web/src/pages/canvas/canvas-project-world-layers.tsx
index 77fb384f3..13c14541c 100644
--- a/web/src/pages/canvas/canvas-project-world-layers.tsx
+++ b/web/src/pages/canvas/canvas-project-world-layers.tsx
@@ -9,6 +9,7 @@ import type { CanvasBatchConnectionPreview } from "@/lib/canvas/canvas-batch-con
 import { sortCanvasNodesByStackOrder, type CanvasNodeStackOrder } from "@/lib/canvas/canvas-node-stack-order";
 import type { CanvasResourceReference } from "@/lib/canvas/canvas-resource-references";
 import { isFrameNode } from "@/lib/canvas/canvas-frame";
+import type { CanvasNodeRenderLOD } from "@/lib/canvas/canvas-node-lod";
 import type { CanvasDisplayConnection, CanvasFolderStyle, CanvasFolderTheme, CanvasNodeData, ConnectionHandle, Position, SelectionBox } from "@/types/canvas";
 
 type DragPreview = { x: number; y: number; nodeIds: Set<string> } | null;
@@ -28,6 +29,7 @@ type CanvasProjectWorldLayersProps = {
     connectionApproach: CanvasConnectionApproach;
     nodeById: Map<string, CanvasNodeData>;
     visibleNodes: CanvasNodeData[];
+    nodeRenderLODById: Map<string, CanvasNodeRenderLOD>;
     nodeStackOrder: CanvasNodeStackOrder;
     frameChildrenById: Map<string, CanvasNodeData[]>;
     linkedFolderPreviewNodesById: Map<string, CanvasNodeData[]>;
@@ -136,6 +138,7 @@ export const CanvasProjectWorldLayers = memo(function CanvasProjectWorldLayers(p
                     <CanvasFrameNode
                         key={node.id}
                         data={node}
+                        renderLOD={props.nodeRenderLODById.get(node.id) || "full"}
                         dragOffset={props.dragPreview?.nodeIds.has(node.id) ? props.dragPreview : undefined}
                         childNodes={framePreviewNodes(node)}
                         scale={viewportScale}
@@ -153,6 +156,7 @@ export const CanvasProjectWorldLayers = memo(function CanvasProjectWorldLayers(p
                     <CanvasNode
                         key={node.id}
                         data={node}
+                        renderLOD={props.nodeRenderLODById.get(node.id) || "full"}
                         dragOffset={props.dragPreview?.nodeIds.has(node.id) ? props.dragPreview : undefined}
                         scale={viewportScale}
                         isSelected={props.selectedNodeIds.has(node.id)}
diff --git a/web/src/pages/canvas/project.tsx b/web/src/pages/canvas/project.tsx
index 6a046e5bc..0fa52fa57 100644
--- a/web/src/pages/canvas/project.tsx
+++ b/web/src/pages/canvas/project.tsx
@@ -1409,6 +1409,7 @@ function InfiniteCanvasPage() {
         imageEditNode,
         mentionReferencesByNodeId,
         nodeById,
+        nodeRenderLODById,
         previewNode,
         reduceMediaEffects,
         relatedHighlight,
@@ -2692,6 +2693,7 @@ function InfiniteCanvasPage() {
                                                 connectionTargetNodeId={connectionTargetNodeId}
                                                 nodeById={nodeById}
                                                 visibleNodes={visibleNodes}
+                                                nodeRenderLODById={nodeRenderLODById}
                                                 nodeStackOrder={nodeStackOrder}
                                                 frameChildrenById={frameChildrenById}
                                                 linkedFolderPreviewNodesById={linkedFolderPreviewNodesById}
diff --git a/web/src/pages/canvas/use-canvas-active-tasks.ts b/web/src/pages/canvas/use-canvas-active-tasks.ts
index 0375c0b5a..a81387d79 100644
--- a/web/src/pages/canvas/use-canvas-active-tasks.ts
+++ b/web/src/pages/canvas/use-canvas-active-tasks.ts
@@ -1,20 +1,39 @@
 import { useEffect } from "react";
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 
-import { listGenerationTasks, type GenerationTask } from "@/services/api/task-center";
+import { listGenerationTasks, subscribeGenerationTasks, type GenerationTask } from "@/services/api/task-center";
 
 export function useCanvasActiveTasks(projectId: string, enabled: boolean) {
+    const queryClient = useQueryClient();
     const query = useQuery<GenerationTask[]>({
         queryKey: ["canvas-active-tasks", projectId],
         // Agent 的持久化执行仍复用任务队列/计费生命周期，但不应占据画布右上角的“生成任务”浮层。
         // 多取一页再过滤，避免 Agent 排在前面时把真正的画布生成任务挤掉。
-        queryFn: () => listGenerationTasks(30, { projectId, activeOnly: true }).then((tasks) => tasks.filter((task) => !isInternalAgentTask(task)).slice(0, 5)),
+        queryFn: ({ signal }) => listGenerationTasks(30, { projectId, activeOnly: true }, undefined, signal).then((tasks) => tasks.filter((task) => !isInternalAgentTask(task)).slice(0, 5)),
         enabled: enabled && Boolean(projectId),
-        refetchInterval: (current) => (current.state.data?.length ? 2_000 : 10_000),
+        // Shared task observers provide live updates. Lists only discover missed/new tasks.
+        refetchInterval: 10_000,
+        refetchIntervalInBackground: false,
         refetchOnWindowFocus: true,
     });
 
+    const taskIds = JSON.stringify((query.data || []).map((task) => task.id).sort());
     useEffect(() => {
+        if (!enabled || !projectId) return;
+        return subscribeGenerationTasks(JSON.parse(taskIds) as string[], (task) => {
+            if (task.projectId !== projectId || isInternalAgentTask(task)) return;
+            queryClient.setQueryData<GenerationTask[]>(["canvas-active-tasks", projectId], (current) => {
+                if (!current) return current;
+                const previous = current.find((item) => item.id === task.id);
+                if (!previous || previous.updatedAt > task.updatedAt) return current;
+                if (task.status !== "queued" && task.status !== "running") return current.filter((item) => item.id !== task.id);
+                return current.map((item) => item.id === task.id ? task : item);
+            });
+        });
+    }, [enabled, projectId, queryClient, taskIds]);
+
+    useEffect(() => {
+        if (!enabled || !projectId) return;
         const handleTaskChanged = (event: Event) => {
             const task = (event as CustomEvent<{ task?: GenerationTask }>).detail?.task;
             if (task?.projectId === projectId) void query.refetch();
@@ -25,7 +44,7 @@ export function useCanvasActiveTasks(projectId: string, enabled: boolean) {
             window.removeEventListener("canvas:task-created", handleTaskChanged);
             window.removeEventListener("canvas:task-cancelled", handleTaskChanged);
         };
-    }, [projectId, query.refetch]);
+    }, [enabled, projectId, query.refetch]);
 
     return {
         tasks: query.data || [],
diff --git a/web/src/pages/canvas/use-canvas-project-lifecycle.ts b/web/src/pages/canvas/use-canvas-project-lifecycle.ts
index b08016c74..0932b240c 100644
--- a/web/src/pages/canvas/use-canvas-project-lifecycle.ts
+++ b/web/src/pages/canvas/use-canvas-project-lifecycle.ts
@@ -254,12 +254,12 @@ export function useCanvasProjectLifecycle({
     useEffect(() => {
         if (!projectLoaded || historyPausedRef.current) return;
         const snapshot = { nodes, connections, chatSessions, activeChatId, canvasAppearance, backgroundMode, showImageInfo };
-        if (!observedContentRef.current || JSON.stringify(observedContentRef.current) === JSON.stringify(snapshot)) return;
+        if (!observedContentRef.current || sameCanvasHistorySnapshot(observedContentRef.current, snapshot)) return;
         observedContentRef.current = snapshot;
         const patch = { nodes, connections, chatSessions, activeChatId, appearance: canvasAppearance, backgroundMode, showImageInfo };
         const stored = useCanvasStore.getState().projects.find((project) => project.id === projectId);
         // 远端结果投影到编辑器不是一次本地编辑，避免改写时间戳并触发反向保存。
-        if (stored && Object.entries(patch).every(([key, value]) => JSON.stringify(stored[key as keyof CanvasProject]) === JSON.stringify(value))) return;
+        if (stored && sameCanvasPatch(stored, patch)) return;
         updateProject(projectId, patch);
     }, [activeChatId, backgroundMode, canvasAppearance, chatSessions, connections, historyPausedRef, nodes, projectId, projectLoaded, showImageInfo, updateProject]);
 
@@ -317,7 +317,7 @@ export function useCanvasProjectLifecycle({
 
     const persistLocalEdits = useCallback(async () => {
         const snapshot = { nodes: nodesRef.current, connections: connectionsRef.current, chatSessions, activeChatId, canvasAppearance, backgroundMode, showImageInfo };
-        if (observedContentRef.current && JSON.stringify(observedContentRef.current) !== JSON.stringify(snapshot)) {
+        if (observedContentRef.current && !sameCanvasHistorySnapshot(observedContentRef.current, snapshot)) {
             updateProject(projectId, {
                 nodes: nodesRef.current,
                 connections: connectionsRef.current,
@@ -407,6 +407,26 @@ export function useCanvasProjectLifecycle({
 }
 
 
+function sameCanvasHistorySnapshot(left: CanvasHistorySnapshot, right: CanvasHistorySnapshot) {
+    return left.nodes === right.nodes
+        && left.connections === right.connections
+        && left.chatSessions === right.chatSessions
+        && left.activeChatId === right.activeChatId
+        && left.canvasAppearance === right.canvasAppearance
+        && left.backgroundMode === right.backgroundMode
+        && left.showImageInfo === right.showImageInfo;
+}
+
+function sameCanvasPatch(project: CanvasProject, patch: Pick<CanvasProject, "nodes" | "connections" | "chatSessions" | "activeChatId" | "backgroundMode" | "showImageInfo"> & { appearance: CanvasProject["appearance"] }) {
+    return project.nodes === patch.nodes
+        && project.connections === patch.connections
+        && project.chatSessions === patch.chatSessions
+        && project.activeChatId === patch.activeChatId
+        && project.appearance === patch.appearance
+        && project.backgroundMode === patch.backgroundMode
+        && project.showImageInfo === patch.showImageInfo;
+}
+
 function mergeHydratedSessions(currentSessions: CanvasAssistantSession[], hydratedSessions: CanvasAssistantSession[]) {
     const hydratedById = new Map(hydratedSessions.map((session) => [session.id, session]));
     return currentSessions.map((session) => {
diff --git a/web/src/pages/canvas/use-canvas-render-model.ts b/web/src/pages/canvas/use-canvas-render-model.ts
index be1878740..f6b208394 100644
--- a/web/src/pages/canvas/use-canvas-render-model.ts
+++ b/web/src/pages/canvas/use-canvas-render-model.ts
@@ -1,4 +1,4 @@
-import { useEffect, useMemo, useRef } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 
 import { buildNodeGenerationInputs, type NodeGenerationInput } from "@/components/canvas/canvas-node-generation";
 import { isFrameNode } from "@/lib/canvas/canvas-frame";
@@ -7,7 +7,8 @@ import { canvasNodeRenderBudget, canvasNodeRenderPadding, CANVAS_MAX_RENDERED_CO
 import { buildCanvasNodeMentionReferenceMap, buildCanvasResourceReferences, buildToolMentionReference, parseToolMentionTokens } from "@/lib/canvas/canvas-resource-references";
 import { buildSkillMentionReferences } from "@/lib/canvas/canvas-skill-mentions";
 import { buildCanvasSpatialIndex, canvasNodeBounds, type CanvasSpatialIndex, type CanvasSpatialIndexEntry } from "@/lib/canvas/canvas-spatial-index";
-import { selectCanvasVisibleNodes } from "@/lib/canvas/canvas-node-visibility";
+import { canvasOverviewMode, resolveCanvasNodeLOD, type CanvasNodeRenderLOD } from "@/lib/canvas/canvas-node-lod";
+import { intersectsCanvasBounds, selectCanvasVisibleNodes } from "@/lib/canvas/canvas-node-visibility";
 import type { Skill } from "@/services/api/skills";
 import type { Asset, ImageAsset } from "@/stores/use-asset-store";
 import type { DirectorScene } from "@/types/director";
@@ -176,7 +177,8 @@ export function useCanvasRenderModel({
         return index;
     }, [nodes]);
     const renderedNodeIdsRef = useRef<Set<string>>(new Set());
-    const visibleNodes = useMemo(() => {
+    const forcedRenderNodeIds = useMemo(() => new Set([...selectedNodeIds, ...(dragPreview?.nodeIds || [])]), [dragPreview, selectedNodeIds]);
+    const candidateNodes = useMemo(() => {
         const frames: CanvasNodeData[] = [];
         const regular: CanvasNodeData[] = [];
         selectCanvasVisibleNodes({
@@ -185,13 +187,74 @@ export function useCanvasRenderModel({
             ...renderBounds,
             hiddenIds: renderHiddenNodeIds,
             retainedIds: renderedNodeIdsRef.current,
-            forcedIds: new Set([...selectedNodeIds, ...(dragPreview?.nodeIds || [])]),
+            forcedIds: forcedRenderNodeIds,
             budget: canvasNodeRenderBudget(viewport.k),
         }).forEach((node) => {
             (isFrameNode(node) ? frames : regular).push(node);
         });
         return [...frames, ...regular];
-    }, [dragPreview, nodeById, nodeSpatialIndex, renderBounds, renderHiddenNodeIds, selectedNodeIds, viewport.k]);
+    }, [forcedRenderNodeIds, nodeById, nodeSpatialIndex, renderBounds, renderHiddenNodeIds, viewport.k]);
+    const immediateRenderNodeIds = useMemo(() => {
+        const ids = new Set(forcedRenderNodeIds);
+        candidateNodes.forEach((node) => {
+            if (ids.has(node.id) || intersectsCanvasBounds(canvasNodeBounds(node), renderBounds.view)) ids.add(node.id);
+        });
+        return ids;
+    }, [candidateNodes, forcedRenderNodeIds, renderBounds.view]);
+    const [mountedNodeIds, setMountedNodeIds] = useState<Set<string>>(() => new Set());
+    useEffect(() => {
+        const candidateIds = new Set(candidateNodes.map((node) => node.id));
+        setMountedNodeIds((current) => {
+            const next = new Set<string>();
+            current.forEach((id) => {
+                if (candidateIds.has(id)) next.add(id);
+            });
+            immediateRenderNodeIds.forEach((id) => next.add(id));
+            return next.size === current.size && [...next].every((id) => current.has(id)) ? current : next;
+        });
+        const queue = candidateNodes
+            .filter((node) => !immediateRenderNodeIds.has(node.id))
+            .sort((left, right) => {
+                const leftDistance = distanceToBounds(canvasNodeBounds(left), renderBounds.view);
+                const rightDistance = distanceToBounds(canvasNodeBounds(right), renderBounds.view);
+                return leftDistance - rightDistance;
+            });
+        let cursor = 0;
+        let frameId = 0;
+        const schedule = () => {
+            frameId = requestAnimationFrame(() => {
+                const startedAt = performance.now();
+                const additions: string[] = [];
+                while (cursor < queue.length && additions.length < 12 && performance.now() - startedAt < 4) additions.push(queue[cursor++].id);
+                if (additions.length) {
+                    setMountedNodeIds((current) => {
+                        if (additions.every((id) => current.has(id))) return current;
+                        const next = new Set(current);
+                        additions.forEach((id) => next.add(id));
+                        return next;
+                    });
+                }
+                if (cursor < queue.length) schedule();
+            });
+        };
+        if (queue.length && typeof window !== "undefined") schedule();
+        return () => cancelAnimationFrame(frameId);
+    }, [candidateNodes, immediateRenderNodeIds, renderBounds.view]);
+    const visibleNodes = useMemo(() => candidateNodes.filter((node) => immediateRenderNodeIds.has(node.id) || mountedNodeIds.has(node.id)), [candidateNodes, immediateRenderNodeIds, mountedNodeIds]);
+    const overviewRef = useRef(false);
+    const overview = canvasOverviewMode(viewport.k, overviewRef.current);
+    useEffect(() => { overviewRef.current = overview; }, [overview]);
+    const nodeRenderLODById = useMemo(() => {
+        const result = new Map<string, CanvasNodeRenderLOD>();
+        for (const node of visibleNodes) {
+            // Selection/drag keeps every node visible, not every editor mounted.
+            const editing = selectedNodeIds.size === 1 && selectedNodeIds.has(node.id);
+            const inView = intersectsCanvasBounds(canvasNodeBounds(node), renderBounds.view);
+            const inEntry = intersectsCanvasBounds(canvasNodeBounds(node), renderBounds.enter);
+            result.set(node.id, resolveCanvasNodeLOD(overview, inView, inEntry, editing));
+        }
+        return result;
+    }, [overview, selectedNodeIds, renderBounds.enter, renderBounds.view, visibleNodes]);
     useEffect(() => {
         renderedNodeIdsRef.current = new Set(visibleNodes.map((node) => node.id));
     }, [visibleNodes]);
@@ -397,6 +460,7 @@ export function useCanvasRenderModel({
         imageEditNode,
         mentionReferencesByNodeId,
         nodeById,
+        nodeRenderLODById,
         previewNode,
         reduceMediaEffects,
         relatedHighlight,
@@ -413,3 +477,9 @@ export function useCanvasRenderModel({
         visibleNodes,
     };
 }
+
+function distanceToBounds(node: { left: number; top: number; right: number; bottom: number }, bounds: { left: number; top: number; right: number; bottom: number }) {
+    const dx = node.right < bounds.left ? bounds.left - node.right : node.left > bounds.right ? node.left - bounds.right : 0;
+    const dy = node.bottom < bounds.top ? bounds.top - node.bottom : node.top > bounds.bottom ? node.top - bounds.bottom : 0;
+    return Math.hypot(dx, dy);
+}
diff --git a/web/src/services/user-data-sync.ts b/web/src/services/user-data-sync.ts
index 44ac5b0f6..c26638ee0 100644
--- a/web/src/services/user-data-sync.ts
+++ b/web/src/services/user-data-sync.ts
@@ -15,7 +15,7 @@ import type { CanvasProject } from "@/stores/canvas/use-canvas-store";
 import { flushCanvasStorePersistence, useCanvasStore } from "@/stores/canvas/use-canvas-store";
 import { useSyncProgressStore } from "@/stores/use-sync-progress-store";
 import { useCanvasHistoryStore } from "@/stores/canvas/use-canvas-history-store";
-import { repairMissingCanvasAssets, collectCanvasMediaAssetIds, rebindInconsistentCanvasAssets, type CanvasAssetRebindResult } from "@/services/canvas-asset-repair";
+import { repairMissingCanvasAssets, repairMissingCanvasVideoPreviews, collectCanvasMediaAssetIds, rebindInconsistentCanvasAssets, type CanvasAssetRebindResult } from "@/services/canvas-asset-repair";
 import { canvasNodeToAsset } from "@/lib/canvas/canvas-node-asset";
 import { applyAgentCanvasPatch, type AgentCanvasPatch } from "@/lib/canvas/agent-canvas-patch";
 
@@ -412,6 +412,9 @@ export function scheduleRemoteUserDataSync() {
 
 export function formatLocalSavedRemotePending(localAction: string, error: unknown): string {
     const detail = error instanceof Error && error.message.trim() ? error.message.trim() : "未知错误";
+    if (error instanceof ApiError && error.reason === "canvas_history_resources_missing") {
+        return `${localAction}，云端同步已暂停：${detail}。请修复缺失素材或从有效历史版本恢复。`;
+    }
     if (error instanceof ApiError && (error.status === 409 || error.status === 428)) {
         return `${localAction}，云端同步已暂停：${detail}。请保留草稿并加载最新版本。`;
     }
@@ -583,9 +586,9 @@ export async function deleteCanvasProjectsWithRemoteSync(ids: string[]) {
     });
 }
 
-export async function saveRemoteUserDataNow(input?: string | readonly string[] | { force?: boolean }) {
+export async function saveRemoteUserDataNow(input?: string | readonly string[] | { force?: boolean; repairMissingResources?: boolean }) {
     const projectId = typeof input === "string" || Array.isArray(input) ? input as string | readonly string[] : undefined;
-    const options = input && typeof input === "object" && !Array.isArray(input) ? input as { force?: boolean } : {};
+    const options = input && typeof input === "object" && !Array.isArray(input) ? input as { force?: boolean; repairMissingResources?: boolean } : {};
     const epoch = sessionEpoch;
     if (!activeRemoteUserId) throw new Error("尚未建立云端同步会话，本地内容尚未保存到云端");
     requireRemoteUserDataBaseline();
@@ -602,6 +605,11 @@ export async function saveRemoteUserDataNow(input?: string | readonly string[] |
         syncQueued = true;
         await syncPromise;
         assertNoConflict();
+        // The in-flight drain may have started before this explicit repair/force
+        // request. Re-enter after it settles so the user's intent is not lost.
+        if (options.force || options.repairMissingResources) {
+            return saveRemoteUserDataNow(input);
+        }
         return;
     }
     syncPromise = withRemoteUserDataSyncExclusive(async () => {
@@ -630,6 +638,8 @@ export async function forceOverwriteRemoteCanvasSync(): Promise<CanvasAssetRebin
     const rebind = await withRemoteUserDataSyncExclusive(async () => {
         if (epoch !== sessionEpoch) throw new Error("账号已切换，已停止修复保存");
         requireRemoteUserDataBaseline();
+        await repairMissingCanvasVideoPreviews();
+        if (epoch !== sessionEpoch) throw new Error("账号已切换，已停止修复保存");
         const projects = useCanvasStore.getState().projects;
         // 服务端素材记录是 guard 实际校验的事实；本地缓存可能落后，须先取回再判定绑定一致性。
         const claimedIds = [...collectCanvasMediaAssetIds(projects)];
@@ -638,17 +648,18 @@ export async function forceOverwriteRemoteCanvasSync(): Promise<CanvasAssetRebin
             const { assets } = await getRemoteAssetsByIds(claimedIds.slice(offset, offset + 100));
             remoteAssets.push(...assets);
         }
+        if (epoch !== sessionEpoch) throw new Error("账号已切换，已停止修复保存");
         const remoteById = new Map(remoteAssets.map((asset) => [asset.id, asset]));
         const merged = [...remoteAssets, ...useAssetStore.getState().assets.filter((asset) => !remoteById.has(asset.id))];
         const result = rebindInconsistentCanvasAssets(parseAssetRecordList(merged));
         await Promise.all([flushCanvasStorePersistence(), flushAssetStorePersistence()]);
         return result;
     });
-    await saveRemoteUserDataNow({ force: true });
+    await saveRemoteUserDataNow({ force: true, repairMissingResources: true });
     return rebind;
 }
 
-async function drainRemoteUserDataChanges(options: { force?: boolean } = {}) {
+async function drainRemoteUserDataChanges(options: { force?: boolean; repairMissingResources?: boolean } = {}) {
     const uploaded = new Map<string, string>();
     do {
         syncQueued = false;
@@ -656,7 +667,7 @@ async function drainRemoteUserDataChanges(options: { force?: boolean } = {}) {
     } while (syncQueued);
 }
 
-async function saveRemoteUserDataBatch(uploaded: Map<string, string>, options: { force?: boolean } = {}) {
+async function saveRemoteUserDataBatch(uploaded: Map<string, string>, options: { force?: boolean; repairMissingResources?: boolean } = {}) {
     // 中央兜底：任何调用方只要把持久媒体写进画布，提交前都会先补齐素材记录与 assetId。
     // 页面级入口仍主动入库，以便立即反馈；这里负责阻止遗漏入口形成远端幽灵资源。
     const changedProjectIds = new Set(useCanvasStore.getState().projects.filter((project) => !sameCanvasContent(acknowledgedProjects.get(project.id), project)).map((project) => project.id));
@@ -719,7 +730,7 @@ async function saveRemoteUserDataBatch(uploaded: Map<string, string>, options: {
                     message: "正在保存画布结构",
                 });
             }
-            const { project: saved } = await upsertRemoteCanvasProject(sanitizeCanvasProjectForRemoteSync(remotePayload));
+            const { project: saved } = await upsertRemoteCanvasProject(sanitizeCanvasProjectForRemoteSync(remotePayload), { repairMissingResources: options.repairMissingResources === true });
             if (!Number.isSafeInteger(saved.revision) || saved.revision !== source.revision! + 1) {
                 throw new ApiError("服务端未返回有效画布版本，请加载云端最新版本", { status: 409 });
             }
@@ -739,7 +750,7 @@ async function saveRemoteUserDataBatch(uploaded: Map<string, string>, options: {
             useSyncProgressStore.getState().setProjectProgress(source.id, { phase: pending ? "pending" : "done", message: pending ? "有新修改等待保存" : "已保存到云端" });
             if (pending) syncQueued = true;
         } catch (error) {
-            const conflict = error instanceof ApiError && (error.status === 409 || error.status === 428);
+            const conflict = error instanceof ApiError && error.reason !== "canvas_history_resources_missing" && (error.status === 409 || error.status === 428);
             useSyncProgressStore.getState().setProjectProgress(source.id, {
                 phase: conflict ? "conflict" : "error",
                 message: error instanceof Error ? error.message : "云端同步失败，等待重试",
diff --git a/web/src/stores/canvas/use-canvas-store.ts b/web/src/stores/canvas/use-canvas-store.ts
index a7e11a43b..c3a60899d 100644
--- a/web/src/stores/canvas/use-canvas-store.ts
+++ b/web/src/stores/canvas/use-canvas-store.ts
@@ -512,6 +512,10 @@ export const useCanvasStore = create<CanvasStore>()(
                 const current = state.projects.find((project) => project.id === id);
                 if (!current) return state;
                 const next = { ...current, ...patch };
+                if (Object.keys(patch).every((key) => key === "viewport")) {
+                    if (samePersistenceValue(current.viewport, next.viewport)) return state;
+                    return { projects: state.projects.map((project) => project === current ? next : project) };
+                }
                 const contentChanged = !sameCanvasContent(current, next);
                 if (!contentChanged && samePersistenceValue(current.viewport, next.viewport)) return state;
                 if (contentChanged) next.updatedAt = new Date().toISOString();
diff --git a/web/test/canvas-node-lod.test.ts b/web/test/canvas-node-lod.test.ts
new file mode 100644
index 000000000..85796b6be
--- /dev/null
+++ b/web/test/canvas-node-lod.test.ts
@@ -0,0 +1,27 @@
+import { describe, expect, test } from "bun:test";
+import { readFileSync } from "node:fs";
+import { canvasOverviewMode, resolveCanvasNodeLOD } from "../src/lib/canvas/canvas-node-lod";
+
+describe("canvas overview rendering", () => {
+    test("uses hysteresis without retaining full editors at 5%", () => {
+        expect(canvasOverviewMode(0.05, false)).toBe(true);
+        expect(canvasOverviewMode(0.24, false)).toBe(false);
+        expect(canvasOverviewMode(0.24, true)).toBe(true);
+        expect(canvasOverviewMode(0.27, true)).toBe(false);
+    });
+    test("keeps 5000 visible representations without 5000 business editors", () => {
+        const levels = Array.from({ length: 5000 }, (_, i) => resolveCanvasNodeLOD(true, true, true, i === 23));
+        expect(levels.filter((level) => level === "full")).toHaveLength(1);
+        expect(levels.filter((level) => level === "preview")).toHaveLength(4999);
+        expect(resolveCanvasNodeLOD(false, true, true, false)).toBe("full");
+        expect(resolveCanvasNodeLOD(true, false, false, false)).toBe("shell");
+        expect(resolveCanvasNodeLOD(true, false, false, true)).toBe("full");
+    });
+    test("wires LOD into both node kinds and the memo comparator", () => {
+        const world = readFileSync(new URL("../src/pages/canvas/canvas-project-world-layers.tsx", import.meta.url), "utf8");
+        const node = readFileSync(new URL("../src/components/canvas/canvas-node.tsx", import.meta.url), "utf8");
+        expect(world.match(/renderLOD=\{props.nodeRenderLODById/g)).toHaveLength(2);
+        expect(node).toContain("previous.renderLOD === next.renderLOD");
+        expect(node).not.toContain('|| isSelected || Boolean(dragOffset) ? "full"');
+    });
+});