feat: 四端设计总览生成、截图补全与模板工具链完善

- 新增 operator/onsite/professional/employee-app 四端 design-overview.html
- 补全约 30 张弹窗/状态截图，重拍长图（fullPage）
- 新增 design-overview-template.html 模板与 design-overview skill
- index.html 注册设计总览入口、修复 md-viewer 路径
- 删除已迁移的 md-viewer.html 和本地服务器方案文档
- 更新 package.json 依赖与项目背景文档

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,9 +1,16 @@
 {
-  "dependencies": {
-    "chrome-devtools-mcp": "^0.21.0"
-  },
+  "name": "platform-prototype",
+  "version": "1.0.0",
+  "main": "server.js",
   "devDependencies": {
-    "playwright": "^1.59.1",
-    "puppeteer-core": "^24.43.0"
-  }
+    "puppeteer": "^24.43.1"
+  },
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "start": "node server.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": ""
 }