更新依赖项，添加 user-agents 库；重构浏览器启动逻辑，支持无头模式和隐身模式

package.json

@@ -40,6 +40,7 @@
   "dependencies": {
     "better-sqlite3": "^12.5.0",
     "playwright": "^1.57.0",
+    "user-agents": "^1.1.669",
     "zod": "^4.2.1",
     "zod-to-json-schema": "^3.25.1"
   },
@@ -52,6 +53,7 @@
     "@types/better-sqlite3": "^7.6.13",
     "@types/bun": "^1.3.5",
     "@types/node": "^25.0.3",
+    "@types/user-agents": "^1.0.4",
     "commander": "^14.0.2",
     "dotenv": "^17.2.3",
     "drizzle-kit": "^0.31.8",