refactor: use request attributes instead of merge for middleware data transfer

- Replace request->merge() with request->attributes->set() in Server middleware to avoid polluting user input
- Add getNodeInfo() helper method in UniProxyController for cleaner node info access
- Update all node_info references to use the new attribute-based approach

app/Http/Middleware/Server.php

@@ -23,7 +23,7 @@ class Server
             throw new ApiException('Server does not exist');
         }
 
-        $request->merge(['node_info' => $serverInfo]);
+        $request->attributes->set('node_info', $serverInfo);
         return $next($request);
     }