Fix WebSocket connection hanging - send connection_successful message

- Change greeting message type from 'message_response' to 'connection_successful'
- Frontend expects connection_successful to complete WebSocket handshake
- This should fix the 'loading' state that never completes
- Users will now see the welcome message and can start chatting

enhanced_websocket_handler.py

@@ -160,7 +160,7 @@ How can I assist you today? You can ask me about any government policies, proced
 
     # Send text greeting
     await websocket.send_json({
-        "type": "message_response",
+        "type": "connection_successful",
         "message": greeting_text,
         "provider_used": "system",
         "capabilities": {