refactor: 将访问令牌功能迁移至模块系统

- 新增 management_tokens 模块定义，支持通过环境变量控制可用性
- 从静态路由中移除 management-tokens，改由模块动态注册
- 前端路由添加模块激活检查，未激活时重定向到仪表盘
- 认证服务添加模块激活检查，未激活时禁止令牌认证
- 导航菜单中移除访问令牌入口（保留直接 URL 访问）
- 修复 alembic 迁移脚本格式和错误处理

src/api/admin/__init__.py

@@ -6,14 +6,13 @@ from .adaptive import router as adaptive_router
 from .api_keys import router as api_keys_router
 from .billing import router as billing_router
 from .endpoints import router as endpoints_router
-from .management_tokens import router as management_tokens_router
 from .models import router as models_router
 from .modules import router as modules_router
 from .monitoring import router as monitoring_router
+from .provider_oauth import router as provider_oauth_router
 from .provider_ops import router as provider_ops_router
 from .provider_query import router as provider_query_router
 from .provider_strategy import router as provider_strategy_router
-from .provider_oauth import router as provider_oauth_router
 from .providers import router as providers_router
 from .security import router as security_router
 from .stats import router as stats_router
@@ -38,12 +37,12 @@ router.include_router(models_router)
 router.include_router(security_router)
 router.include_router(stats_router)
 router.include_router(provider_query_router)
-router.include_router(management_tokens_router)
 router.include_router(modules_router)
 router.include_router(provider_ops_router)
 router.include_router(video_tasks_router)
 
-# 注意：ldap_router 已迁移到模块系统，由 ModuleRegistry 动态注册
-# 当 LDAP_AVAILABLE=true 时才会注册路由
+# 注意：以下路由已迁移到模块系统，由 ModuleRegistry 动态注册
+# - ldap_router: 当 LDAP_AVAILABLE=true 时注册
+# - management_tokens_router: 当 MANAGEMENT_TOKENS_AVAILABLE=true 时注册
 
 __all__ = ["router"]