feat: 接入法制日报机构并新增 15 应用 Playwright 回归测试

- 新增法制日报机构种子数据（机构/用户/分类/15应用/知识库），登录页默认账号预填
- 引入 Playwright e2e：登录复用 storageState，覆盖对话/补全/工作流/智能体四类交互
- 配置测试脚本与产物 gitignore

Co-authored-by: Cursor <cursor@cursor.com>

apps/web/package.json

@@ -6,7 +6,10 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint"
+    "lint": "eslint",
+    "test:e2e": "playwright test",
+    "test:e2e:ui": "playwright test --ui",
+    "test:e2e:report": "playwright show-report e2e/.report"
   },
   "dependencies": {
     "@base-ui/react": "^1.4.1",
@@ -30,6 +33,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.0.0",
+    "@playwright/test": "^1.61.1",
     "@tailwindcss/postcss": "^4",
     "@types/node": "^20",
     "@types/react": "^19",