refactor(repo): consolidate openflare-server to root and move subprojects to internal/apps

- Merge all files inside openflare-server to the repository root directory.
- Relocate agent, relay, and flared subprojects from internal/ to internal/apps/.
- Combine docker-compose files and update build context paths to root.
- Update GitHub workflows and Dockerfiles to refer to new directories and package names.
- Rewrite Go package imports across all files.
- Resolve database renew test race condition and clean up docs.

frontend/lib/services/core/index.ts

@@ -0,0 +1,27 @@
+/**
+ * 核心服务模块
+ * 提供 API 请求的基础设施
+ */
+
+export { default as apiClient, cancelRequest, cancelAllRequests } from './api-client';
+export { BaseService } from './base.service';
+export { apiConfig } from './config';
+export {
+  ApiErrorBase,
+  NetworkError,
+  TimeoutError,
+  UnauthorizedError,
+  ForbiddenError,
+  NotFoundError,
+  ServerError,
+  ValidationError,
+  isCancelError,
+} from './errors';
+export type {
+  ApiResponse,
+  ApiError,
+  PaginationParams,
+  PaginationResponse,
+  RequestConfig,
+} from './types';
+