feat(render): M2 — React 渲染内核 + 布局画廊(playground)

- core 新增 render 子路径(vibe-registry/render):PageView + WidgetView + LayoutGallery
- layout 注册项支持 render 实现;缺省兜底 DefaultLayout
- widget 注册项 component 挂真实 React 组件
- PageBlockDecl 增加 slot 字段(块落在布局哪个槽位)
- playground:admin 布局真实骨架 + 组件 + 订单页,dev 预览 + 生产构建通过
- 全量回归:core/qa-orchestrator/playground typecheck 全绿

package.json

@@ -6,14 +6,20 @@
   "description": "万物皆注册 · 面向 AI 前端的注册式页面框架(M1 概念验证)",
   "main": "./src/index.ts",
   "exports": {
-    ".": "./src/index.ts"
+    ".": "./src/index.ts",
+    "./render": "./src/render.ts"
   },
   "scripts": {
     "typecheck": "tsc --noEmit",
     "vr": "node --experimental-strip-types cli/vr.ts"
   },
+  "peerDependencies": {
+    "react": ">=18"
+  },
   "devDependencies": {
     "@types/node": "^22.0.0",
+    "@types/react": "^18.3.0",
+    "react": "^18.3.0",
     "typescript": "^5.8.0"
   }
 }