feat(log): 解耦用户访问日志存储，支持切换日志主库

用户访问日志可在 ClickHouse、PostgreSQL、SQLite 之间切换。
关闭 ClickHouse 时由主库承接写入与查询；切换任务会冻结写入、复制数据后翻转主库。
启动时校验日志主库与运行配置一致，定期清理按各库保留天数删除过期记录。

frontend/lib/services/admin/status.service.ts

@@ -1,5 +1,5 @@
 import { BaseService } from '@/lib/services/core';
-import type { AppUpdateStatus, SystemStatus } from './types';
+import type { AppUpdateStatus, LogDatabaseStatus, SystemStatus } from './types';
 
 export class AdminStatusService extends BaseService {
   protected static readonly basePath = '/api/v1/admin';
@@ -8,6 +8,10 @@ export class AdminStatusService extends BaseService {
     return this.get<SystemStatus>('/status');
   }
 
+  static async getLogDatabaseStatus(): Promise<LogDatabaseStatus> {
+    return this.get<LogDatabaseStatus>('/status/log-database');
+  }
+
   static async getUpdateStatus(): Promise<AppUpdateStatus> {
     return this.get<AppUpdateStatus>('/update');
   }