Show WeCom machine name after brand title on shell and login.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/api/client.ts

@@ -32,6 +32,18 @@ export function getUsername(): string | null {
   return localStorage.getItem(USER_KEY);
 }
 
+/** 与企微通知同一机器名（公开接口，登录前可用）。 */
+export async function fetchMachineName(): Promise<string> {
+  try {
+    const res = await fetch(`${getApiBase()}/api/auth/branding`);
+    if (!res.ok) return "";
+    const data = (await res.json()) as { machine_name?: string };
+    return String(data.machine_name || "").trim();
+  } catch {
+    return "";
+  }
+}
+
 function tokenExpiresAtMs(): number | null {
   const raw = localStorage.getItem(TOKEN_EXP_KEY);
   if (!raw) return null;