UI 原型 kind 判断改用共享常量

- uiDesignResourceBridge.ts：原型 kind 比较由裸字符串 `'ui-design'` 改为 `GAME_CREATION_APP_UI_DESIGN_ASSET_KIND`，与 manifest kind 契约保持同一处定义。

apps/ai-game-creator-shell/src/features/ui-editor/uiDesignResourceBridge.ts

@@ -3,6 +3,7 @@ import type {
   GameCreationAppManifest,
 } from '../../../../../packages/shared/src/contracts/gameCreationApp';
 import {
+  GAME_CREATION_APP_UI_DESIGN_ASSET_KIND,
   GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
   GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
 } from '../../../../../packages/shared/src/contracts/gameCreationApp';
@@ -93,7 +94,7 @@ export async function ensureUiDesignResourceForPrototype({
     parseGameCreationAppAssetKind(
       prototype.kind,
       'ui-design-resource-bridge.prototype',
-    ) !== 'ui-design'
+    ) !== GAME_CREATION_APP_UI_DESIGN_ASSET_KIND
   ) {
     throw new Error('目标资源不是 UI 原型图片');
   }