修复素材图层创建失败时误切换上传目录

将上传目录切换延后到素材图层构建成功之后。
构建失败时保持原目录并展示错误，补充回归测试。

src/components/image-editor/useImageCanvasAssetCanvasBridge.test.tsx

@@ -74,6 +74,7 @@ function AssetCanvasBridgeHarness({
   appendCanvasLayersWithResources = vi.fn(),
   captureCanvasHistory = vi.fn(),
   selectSingleLayer = vi.fn(),
+  onAssetError = vi.fn(),
 }: {
   asset?: EditorAsset;
   resolveCanvasPoint?: (clientX: number, clientY: number) => {
@@ -83,6 +84,7 @@ function AssetCanvasBridgeHarness({
   appendCanvasLayersWithResources?: (nextLayers: CanvasLayer[]) => void;
   captureCanvasHistory?: () => void;
   selectSingleLayer?: (layerId: string | null) => void;
+  onAssetError?: (message: string) => void;
 }) {
   const assetPointerDragRef = useRef<AssetPointerDragState | null>({
     assetId: asset.id,
@@ -128,6 +130,7 @@ function AssetCanvasBridgeHarness({
     appendCanvasLayersWithResources,
     selectSingleLayer,
     addUploadedFiles: vi.fn(),
+    onAssetError,
   });
 
   return (
@@ -224,6 +227,37 @@ describe('useImageCanvasAssetCanvasBridge', () => {
     expect(screen.getByTestId('hover').textContent).toBe('-');
   });
 
+  it('keeps the upload folder unchanged when layer creation fails', () => {
+    const appendCanvasLayersWithResources = vi.fn();
+    const captureCanvasHistory = vi.fn();
+    const onAssetError = vi.fn();
+    render(
+      <AssetCanvasBridgeHarness
+        asset={{
+          ...defaultAsset,
+          folderId: 'characters',
+          assetKind: 'character-animation',
+          imageSequenceFrames: [],
+          imageSequenceDurationMs: 1_000,
+        }}
+        appendCanvasLayersWithResources={appendCanvasLayersWithResources}
+        captureCanvasHistory={captureCanvasHistory}
+        onAssetError={onAssetError}
+      />,
+    );
+
+    act(() => {
+      screen.getByRole('button', { name: '添加到画布' }).click();
+    });
+
+    expect(screen.getByTestId('folder').textContent).toBe('project');
+    expect(onAssetError).toHaveBeenCalledWith(
+      '角色动作素材“素材一”不完整：缺少可用序列帧。',
+    );
+    expect(captureCanvasHistory).not.toHaveBeenCalled();
+    expect(appendCanvasLayersWithResources).not.toHaveBeenCalled();
+  });
+
   it('delegates active pointer drops over the canvas into the layer path', () => {
     const appendCanvasLayersWithResources = vi.fn();
     render(

src/components/image-editor/useImageCanvasAssetCanvasBridge.ts

@@ -156,7 +156,6 @@ export function useImageCanvasAssetCanvasBridge({
 }: UseImageCanvasAssetCanvasBridgeOptions) {
   const addAssetLayer = useCallback(
     (asset: EditorAsset, position?: CanvasPoint) => {
-      setActiveUploadFolderId(asset.folderId);
       const nextLayerIndex = layerCounterRef.current + 1;
       let nextLayer: CanvasLayer;
       try {
@@ -176,6 +175,7 @@ export function useImageCanvasAssetCanvasBridge({
         );
         return;
       }
+      setActiveUploadFolderId(asset.folderId);
       layerCounterRef.current = nextLayerIndex;
       captureCanvasHistory({ type: 'add-image', count: 1 });
       appendCanvasLayersWithResources([nextLayer]);