feat(canvas): 画布工作台 - 新增生成副本并修复大型画布性能、素材同步与删除校验

统一图片与视频副本的生成落点并保留参考连接。\n优化大型画布节点虚拟化、媒体懒加载、拖拽与详情进入路径。\n修复素材主版本 ID 同步及删除时的画布独立引用校验。

web/src/lib/canvas/canvas-generation-layout.ts

@@ -10,7 +10,15 @@ const BATCH_CHILD_GAP = 36;
 const NODE_CLEARANCE = 36;
 
 export function canGenerateImageInPlace(sourceNode: CanvasNodeData | undefined) {
-    return sourceNode?.type === CanvasNodeType.Image && !sourceNode.metadata?.content;
+    return canGenerateMediaInPlace(sourceNode, CanvasNodeType.Image);
+}
+
+export function canGenerateMediaInPlace(sourceNode: CanvasNodeData | undefined, mediaType: typeof CanvasNodeType.Image | typeof CanvasNodeType.Video | typeof CanvasNodeType.Audio) {
+    if (sourceNode?.type !== mediaType) return false;
+    if (sourceNode.metadata?.generationResultPlacement) return sourceNode.metadata.generationResultPlacement === "replace-node";
+    if (!sourceNode.metadata?.content) return true;
+    // 兼容显式落点字段引入前创建的复制节点和版本节点。
+    return Boolean(sourceNode.metadata?.copiedFromNodeId || sourceNode.metadata?.versionOfNodeId);
 }
 
 export function imageGenerationGroupSize(rootSize: Size, imageSize: Size, childCount: number): Size {