refactor(canvas): 节点注册表 - 收敛节点展示与几何知识到单一数据源

每加一种画布节点，叫什么、长什么样、能不能自由拉伸要在 4-5 处各写一遍。
实际后果是节点标签出现三份且互相矛盾（NODE_DEFAULT_SIZE.title / 创建菜单 label /
搜索弹窗 nodeTypeLabel），canvas-node-size.ts 里还有第四份硬编码兜底。

新增 lib/canvas/node-registry/，镜像现有 tool-registry/ 的结构：
静态定义带 satisfies Record<CanvasNodeType, ...> 做编译期穷尽性检查
（往枚举加成员不补定义即编译失败），再注册进模块级 Map 并按 ownerId 归属，
为后续扩展留出隔离位。

尺寸与初始 metadata 的数据源仍是 constant/canvas.ts 的 NODE_SPECS，定义文件读它
而非复制，现有约 40 处布局计算未动；渲染层 nodeContentRenderers 已是查表结构，
本次不改。

标签刻意分三个字段各司其职，界面文案零变化：
- defaultTitle 新建节点默认名（Note/Audio/未命名背板 原样保留）
- label UI 短标签
- listLabel 列表标签，缺省派生为 label + 节点；背板显式钉住为背板

接入 3 处调用点：创建菜单标签与图标、搜索弹窗类型标签、canvas-node.tsx 的
minWidth/minHeight 与 keepRatio。导演台落在节点分区但开的是工作台、不是节点类型，
故不走注册表。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

web/src/components/canvas/canvas-node.tsx

@@ -10,7 +10,7 @@ import { useThemeStore } from "@/stores/use-theme-store";
 import { storyboardMinNodeHeight } from "./canvas-script-node";
 import { CanvasNodeType, type CanvasNodeData, type Position } from "@/types/canvas";
 import type { CanvasResourceReference } from "@/lib/canvas/canvas-resource-references";
-import { MEDIA_NODE_MIN_SIZE } from "@/lib/canvas/canvas-node-size";
+import { getNodeMinSize, shouldKeepAspectRatio } from "@/lib/canvas/node-registry";
 import { CanvasNodeContent, CanvasNodeImageInfo } from "./canvas-node-content";
 
 type ResizeCorner = "top-left" | "top-right" | "bottom-left" | "bottom-right";
@@ -176,9 +176,10 @@ export const CanvasNode = React.memo(function CanvasNode({
 
             const dx = (event.clientX - resizeRef.current.startX) / scale;
             const dy = (event.clientY - resizeRef.current.startY) / scale;
-            const isMediaNode = data.type === CanvasNodeType.Image || data.type === CanvasNodeType.Video;
-            const minWidth = data.type === CanvasNodeType.Script ? 800 : isMediaNode ? MEDIA_NODE_MIN_SIZE.width : 220;
-            const minHeight = scriptMinHeight || (isMediaNode ? MEDIA_NODE_MIN_SIZE.height : 160);
+            const minSize = getNodeMinSize(data.type);
+            const minWidth = minSize.width;
+            // 分镜脚本的高度由表格内容动态撑开，覆盖注册表里的静态下限。
+            const minHeight = scriptMinHeight || minSize.height;
             const startRight = resizeRef.current.startLeft + resizeRef.current.startWidth;
             const startBottom = resizeRef.current.startTop + resizeRef.current.startHeight;
             const fromLeft = resizeRef.current.corner.includes("left");
@@ -230,7 +231,7 @@ export const CanvasNode = React.memo(function CanvasNode({
             startTop: data.position.y,
             startWidth: data.width,
             startHeight: data.height,
-            keepRatio: (data.type === CanvasNodeType.Image && !data.metadata?.freeResize) || data.type === CanvasNodeType.Video,
+            keepRatio: shouldKeepAspectRatio(data),
             ratio: (data.metadata?.naturalWidth || data.width) / (data.metadata?.naturalHeight || data.height || 1),
         };
         window.addEventListener("mousemove", handleResizeMove);