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/config.ts

@@ -0,0 +1,27 @@
+/**
+ * API 配置
+ */
+
+/**
+ * 获取 API 基础 URL
+ * @returns API 基础 URL
+ */
+export function getApiBaseUrl(): string {
+  if (typeof window === 'undefined') {
+    return process.env.WAVELET_BACKEND_URL || process.env.NEXT_PUBLIC_WAVELET_BACKEND_URL || 'http://localhost:3000';
+  }
+  return process.env.NEXT_PUBLIC_WAVELET_BACKEND_URL || '';
+}
+
+/**
+ * API 配置选项
+ */
+export const apiConfig = {
+  /** Basic URL */
+  baseURL: getApiBaseUrl(),
+  /** 超时时间（毫秒） */
+  timeout: 15000,
+  /** 携带凭证 */
+  withCredentials: true,
+} as const;
+