修复图片修改参数恢复与提交一致性

- 图片修改面板优先恢复历史模型、比例和尺寸，并保留显式设置优先级

- 图片修改提交计划统一归一化参数并下发 model、aspectRatio、imageSize 和 size

- 画布完成占位使用实际目标输出尺寸

- 补充参数恢复回归测试与编辑器方案说明

src/components/image-editor/ImageCanvasGenerationDialogModel.test.ts

@@ -419,6 +419,41 @@ describe('ImageCanvasGenerationDialogModel', () => {
     expect(createCharacterAnimationPanelDraft(createLayer())).toBeNull();
   });
 
+  it('restores persisted image parameters when creating edit drafts', () => {
+    const sourceLayer = createLayer({
+      model: IMAGE_MODEL_NANOBANANA2,
+      generationInputs: {
+        version: 2,
+        action: 'image.edit',
+        fields: [
+          { id: 'prompt', title: '修改要求', value: '改成雨天' },
+          { id: 'model', title: '模型', value: IMAGE_MODEL_GPT_IMAGE_2 },
+          { id: 'aspectRatio', title: '比例', value: '2:3' },
+          { id: 'imageSize', title: '尺寸', value: '2K' },
+        ],
+        references: [],
+      },
+    });
+
+    expect(createEditDialogDraft(sourceLayer)).toMatchObject({
+      prompt: '改成雨天',
+      imageModel: IMAGE_MODEL_GPT_IMAGE_2,
+      aspectRatio: '2:3',
+      imageSize: '2K',
+    });
+    expect(
+      createEditDialogDraft(sourceLayer, {
+        imageModel: IMAGE_MODEL_NANOBANANA2,
+        aspectRatio: '16:9',
+        imageSize: '1K',
+      }),
+    ).toMatchObject({
+      imageModel: IMAGE_MODEL_NANOBANANA2,
+      aspectRatio: '16:9',
+      imageSize: '1K',
+    });
+  });
+
   it('preserves the resolved asset label in quick-edit dialog snapshots', () => {
     expect(
       createQuickEditGenerationDialogDraft({