更新提现功能，新增私钥文件 URL 配置选项以支持从远程拉取私钥，优化相关错误处理逻辑，确保在转账前正确加载私钥。同时，更新文档以反映新的环境变量配置，提升系统的灵活性和用户体验。

soul-admin/src/api/client.ts

@@ -0,0 +1,77 @@
+/**
+ * 统一 API 请求封装
+ * 规则：API 路径与现网完全一致，仅通过 baseUrl 区分环境（Next 或未来 Gin）
+ * 无缝切换：仅修改 VITE_API_BASE_URL 即可切换后端
+ */
+
+const getBaseUrl = (): string => {
+  const url = import.meta.env.VITE_API_BASE_URL
+  if (typeof url === 'string' && url.length > 0) return url.replace(/\/$/, '')
+  return ''
+}
+
+/** 请求完整 URL：baseUrl + path，path 必须与现网一致（如 /api/orders） */
+export function apiUrl(path: string): string {
+  const base = getBaseUrl()
+  const p = path.startsWith('/') ? path : `/${path}`
+  return base ? `${base}${p}` : p
+}
+
+export type RequestInitWithBody = RequestInit & { data?: unknown }
+
+/**
+ * 发起请求。path 为与现网一致的 API 路径（如 /api/admin、/api/orders）。
+ * 自动带上 credentials: 'include' 以支持 Cookie 鉴权（与现有 Next 一致）。
+ */
+export async function request<T = unknown>(
+  path: string,
+  options: RequestInitWithBody = {}
+): Promise<T> {
+  const { data, ...init } = options
+  const url = apiUrl(path)
+  const headers = new Headers(init.headers as HeadersInit)
+  if (data !== undefined && data !== null && !headers.has('Content-Type')) {
+    headers.set('Content-Type', 'application/json')
+  }
+  const body = data !== undefined && data !== null ? JSON.stringify(data) : init.body
+  const res = await fetch(url, {
+    ...init,
+    headers,
+    body,
+    credentials: 'include',
+  })
+  const contentType = res.headers.get('Content-Type') || ''
+  const json: T = contentType.includes('application/json')
+    ? ((await res.json()) as T)
+    : (res as unknown as T)
+  if (!res.ok) {
+    const err = new Error((json as { error?: string })?.error || `HTTP ${res.status}`) as Error & {
+      status: number
+      data: T
+    }
+    err.status = res.status
+    err.data = json
+    throw err
+  }
+  return json
+}
+
+/** GET */
+export function get<T = unknown>(path: string, init?: RequestInit): Promise<T> {
+  return request<T>(path, { ...init, method: 'GET' })
+}
+
+/** POST */
+export function post<T = unknown>(path: string, data?: unknown, init?: RequestInit): Promise<T> {
+  return request<T>(path, { ...init, method: 'POST', data })
+}
+
+/** PUT */
+export function put<T = unknown>(path: string, data?: unknown, init?: RequestInit): Promise<T> {
+  return request<T>(path, { ...init, method: 'PUT', data })
+}
+
+/** DELETE */
+export function del<T = unknown>(path: string, init?: RequestInit): Promise<T> {
+  return request<T>(path, { ...init, method: 'DELETE' })
+}