fix: mqtt subscription format

- Use gmqtt's Subscription class for MQTT subscriptions
- Updated both _post_connect and subscribe methods

backend/mqtt_integration.py

@@ -3,6 +3,7 @@ import json
 import asyncio
 from typing import Optional, Callable, Union
 from gmqtt import Client as MQTTClient
+from gmqtt.mqtt.subscription import Subscription
 import logging
 
 # Get logger
@@ -102,8 +103,9 @@ class HomeAssistantMQTT:
         logger.info("Connected to MQTT broker")
         self._connected = True
         try:
-            # Subscribe to command topic using a dict
-            await self.client.subscribe([{'topic': self.command_topic, 'qos': 1}])
+            # Subscribe to command topic using gmqtt's format
+            sub = Subscription(self.command_topic, qos=1)
+            await self.client.subscribe([sub])
             logger.info(f"Subscribed to command topic: {self.command_topic}")
             
             # Publish discovery config
@@ -192,7 +194,8 @@ class HomeAssistantMQTT:
         """Subscribe to a topic"""
         if self.client and self._connected:
             try:
-                await self.client.subscribe([{'topic': topic, 'qos': 1}])
+                sub = Subscription(topic, qos=1)
+                await self.client.subscribe([sub])
             except Exception as e:
                 logger.error(f"Failed to subscribe to topic: {e}")