feat: 接口统一优化

app/utils/fetch.ts

@@ -0,0 +1,17 @@
+// app/utils/fetch.ts - $fetch 请求工具
+
+/** 从 `$fetch` 错误里提取安全文案；服务端已经保证 message/msg 不含敏感上游细节 */
+export const getClientErrorMessage = (error: unknown, fallback: string) => {
+  if (typeof error !== "object" || error === null) return fallback;
+
+  const data = "data" in error ? (error as { data?: unknown }).data : undefined;
+  if (typeof data === "object" && data !== null) {
+    const message = (data as { message?: unknown; msg?: unknown }).message;
+    const msg = (data as { message?: unknown; msg?: unknown }).msg;
+
+    if (typeof message === "string" && message) return message;
+    if (typeof msg === "string" && msg) return msg;
+  }
+
+  return fallback;
+};