refactor(admin): 合并管理后台并移除 apps/agent

- 平台与代理共用 apps/admin，统一登录 manage/auth/login
- 按 userType 展示菜单，修复 token 循环跳转
- 删除独立 apps/agent 前端工程

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

package.json

@@ -8,7 +8,7 @@
     "dev:api": "pnpm --filter @thebet365/api dev",
     "dev:player": "pnpm --filter @thebet365/player dev",
     "dev:admin": "pnpm --filter @thebet365/admin dev",
-    "dev:agent": "pnpm --filter @thebet365/agent dev",
+    "dev:manage": "pnpm --filter @thebet365/admin dev",
     "build": "pnpm -r run build",
     "test": "pnpm -r run test",
     "db:generate": "pnpm --filter @thebet365/api db:generate",