revert: restore gvsdsdk role/permission APIs; keep KefuProfile login fix

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

jituan/services/admin_context.py

@@ -102,19 +102,15 @@ def is_system_super_admin(user):
 
 
 def is_kefu_backend_account(user):
-    """可登录客服后台：超管 / UserType=kefu / KefuProfile / 旧表 user_role 有绑定。"""
+    """可登录客服后台：超管 / UserType=kefu / 有正常 KefuProfile。"""
     if is_system_super_admin(user):
         return True
     if getattr(user, 'UserType', '') == 'kefu':
         return True
     try:
-        kefu = user.KefuProfile
-        if kefu.zhuangtai == 1:
-            return True
+        return user.KefuProfile.zhuangtai == 1
     except Exception:
-        pass
-    from backend.utils import has_legacy_backend_binding
-    return has_legacy_backend_binding(user)
+        return False
 
 
 def can_manage_admin_assignments(user, permissions=None):