施工(HEL-226): 实现登录门户与本机免密切换账号

用设备 Cookie 和授权表记住本机已验证账号，登录页按确认样图做成门户，不再把密码写进浏览器。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

backend/features/accounts/routes.py

@@ -6,6 +6,9 @@ class AccountRoutesMixin:
         if parsed.path == "/api/auth/me":
             self.auth_me()
             return True
+        if parsed.path == "/api/auth/accounts":
+            self.auth_accounts()
+            return True
         return False
 
     def _handle_accounts_get(self, parsed) -> bool: