优化画布任务计时与去背景占位

移除画布任务列表的百分比展示

生成中任务显示阶段和已用时，排队任务不计时

去除背景在项目画布中创建生成占位并通过后端快照完成

补充客户端、工作流和后端契约测试

同步图片画布技术文档和项目记忆

src/services/image-editor/editorProjectClient.test.ts

@@ -22,6 +22,7 @@ import {
   loadEditorAssetLibrary,
   loadEditorProject,
   loadOrCreateRecentEditorProject,
+  removeEditorImageBackground,
   renameEditorProject,
   saveEditorProjectLayout,
   updateEditorAsset,
@@ -1389,4 +1390,66 @@ describe('editorProjectClient', () => {
       }),
     );
   });
+
+  it('passes canvas completion context to background removal', async () => {
+    requestJsonMock.mockResolvedValueOnce({
+      imageSrc: 'data:image/png;base64,cutout',
+      width: 512,
+      height: 512,
+      objectKey: 'generated-character-drafts/editor-cutouts/cutout.png',
+      assetObjectId: 'asset-object-cutout',
+      taskId: 'background-removal-1',
+      elapsedMs: 1200,
+      provider: 'BiRefNet',
+      project: null,
+    });
+
+    await removeEditorImageBackground({
+      sourceImageSrc: 'data:image/png;base64,source',
+      projectId: 'editor-project-1',
+      targetLayerId: 'layer-source',
+      canvasCompletion: {
+        dialogId: 'generation-dialog-1',
+        title: '源图 去背景',
+        placeholder: {
+          x: 120,
+          y: 140,
+          width: 320,
+          height: 240,
+          originalWidth: 320,
+          originalHeight: 240,
+        },
+      },
+    });
+
+    expect(requestJsonMock).toHaveBeenCalledWith(
+      '/api/editor/images/background-removals',
+      expect.objectContaining({
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          sourceImageSrc: 'data:image/png;base64,source',
+          projectId: 'editor-project-1',
+          targetLayerId: 'layer-source',
+          canvasCompletion: {
+            dialogId: 'generation-dialog-1',
+            title: '源图 去背景',
+            placeholder: {
+              x: 120,
+              y: 140,
+              width: 320,
+              height: 240,
+              originalWidth: 320,
+              originalHeight: 240,
+            },
+          },
+        }),
+      }),
+      '去除背景失败',
+      expect.objectContaining({
+        timeoutMs: 1_200_000,
+        retry: editorRetryOptionsExpectation,
+      }),
+    );
+  });
 });

src/services/image-editor/editorProjectClient.ts

@@ -209,6 +209,7 @@ export type EditorBackgroundRemovalInput = {
   assetLabel?: string | null;
   sourceResourceId?: string | null;
   taskId?: string | null;
+  canvasCompletion?: EditorCanvasGenerationCompletionInput | null;
 };
 
 export type EditorImageGenerationResult = {
@@ -914,6 +915,9 @@ export async function removeEditorImageBackground(
         ? { sourceResourceId: input.sourceResourceId }
         : {}),
       ...(input.taskId ? { taskId: input.taskId } : {}),
+      ...(input.canvasCompletion
+        ? { canvasCompletion: input.canvasCompletion }
+        : {}),
     }),
     '去除背景失败',
     {