保存图片画布生成器快照

将生成器对话框作为画布布局项序列化和恢复

生成成功后保留生成器快照并锚定到成品图层

图片类生成结果同步写入账号素材库

补充生成器持久化测试和浏览器回归相关文档

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

@@ -218,4 +218,28 @@ describe('ImageCanvasWorldView', () => {
     expect(props.onActivateGenerationDialog).toHaveBeenCalledWith(dialog);
     expect(screen.queryByText('dialog-without-placeholder')).toBeNull();
   });
+
+  it('keeps saved generator placeholders hidden after a result layer exists', () => {
+    renderWorldView({
+      layers: [createLayer({ id: 'layer-generated', title: '生成图片' })],
+      canvasGenerationDialogs: [
+        createGenerationDialog({
+          generatedLayerId: 'layer-generated',
+          placeholder: {
+            x: 80,
+            y: 90,
+            width: 420,
+            height: 420,
+            originalWidth: 2048,
+            originalHeight: 2048,
+          },
+        }),
+      ],
+    });
+
+    expect(screen.getByRole('button', { name: '选择生成图片' })).toBeTruthy();
+    expect(
+      screen.queryByRole('button', { name: '图像生成占位图' }),
+    ).toBeNull();
+  });
 });