补齐场景契约、文档与路由级测试

补全场景技术方案请求字段边界并加入文档总览
共享包出口导出场景运行时常量与类型
新增场景生成路由鉴权、必填校验与内联媒体拒绝测试
后端重建 generationInputs 字段避免透传客户端伪造内容
补齐 scene 画布素材类型标签并新增回归测试

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

@@ -297,6 +297,12 @@ describe('ImageCanvasWorldView', () => {
           title: '角色标签图层',
           assetKind: 'character',
         }),
+        createLayer({
+          id: 'layer-scene',
+          resourceId: 'resource-scene',
+          title: '游戏场景',
+          assetKind: 'scene',
+        }),
         createLayer({
           id: 'layer-source',
           resourceId: 'resource-source',
@@ -310,10 +316,12 @@ describe('ImageCanvasWorldView', () => {
     const characterButton = screen.getByRole('button', {
       name: '选择角色标签图层',
     });
+    const sceneButton = screen.getByRole('button', { name: '选择游戏场景' });
     const sourceButton = screen.getByRole('button', { name: '选择角色原图' });
 
     expect(within(layerButton).getByText('未知')).toBeTruthy();
     expect(within(characterButton).getByText('角色')).toBeTruthy();
+    expect(within(sceneButton).getByText('场景')).toBeTruthy();
     expect(within(sourceButton).getByText('角色')).toBeTruthy();
   });
 

src/components/image-editor/ImageCanvasWorldView.tsx

@@ -220,6 +220,7 @@ const CANVAS_ASSET_KIND_TAG_OPTIONS: Array<{
     className: 'publication-material',
   },
   { value: 'ui-design', label: 'UI设计', className: 'ui-design' },
+  { value: 'scene', label: '场景', className: 'scene' },
   { value: 'video', label: '视频', className: 'video' },
   { value: 'sound-effect', label: '音效', className: 'sound-effect' },
   {