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

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

backend/app/api/auth_routes.py

@@ -98,16 +98,27 @@ async def login(
     )
 
 
+@router.get("/branding")
+async def branding() -> dict:
+    """登录页/顶栏展示用（无敏感信息）：与企微通知同一机器名。"""
+    from ..notify import wecom
+
+    return {"machine_name": wecom.wecom_machine_name() or ""}
+
+
 @router.get("/me")
 async def me(
     username: Annotated[str, Depends(require_user)],
     settings: Annotated[Settings, Depends(get_settings)],
 ) -> dict:
+    from ..notify import wecom
+
     return {
         "username": username,
         "env_name": settings.env_name,
         "mode": settings.mode,
         "sim": settings.is_sim,
+        "machine_name": wecom.wecom_machine_name() or "",
     }