Add optional temperature support to SNMP checker

- New temperature_oid config parameter
- Temperature published as integer via MQTT
- Auto-creates Home Assistant temperature sensor via MQTT Discovery

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lan_checker.py

@@ -121,6 +121,29 @@ class LanChecker:
                 retain=True
             )
 
+            # Sensor for temperature (SNMP only, if temperature_oid configured)
+            if check.get("type") == "snmp" and check.get("temperature_oid"):
+                temp_config = {
+                    "name": f"{device_name} Temperature",
+                    "unique_id": f"lan_checker_{device_id}_temperature",
+                    "state_topic": f"lan_checker/{device_id}/state",
+                    "value_template": "{{ value_json.temperature | default('unavailable') }}",
+                    "unit_of_measurement": "°C",
+                    "device_class": "temperature",
+                    "state_class": "measurement",
+                    "device": {
+                        "identifiers": [f"lan_checker_{device_id}"],
+                        "name": device_name,
+                        "manufacturer": "LAN Checker",
+                    },
+                }
+
+                self.mqtt_client.publish(
+                    f"homeassistant/sensor/lan_checker_{device_id}_temperature/config",
+                    json.dumps(temp_config),
+                    retain=True
+                )
+
             logger.info(f"Published discovery for: {device_name}")
 
     def _setup_checks(self):
@@ -155,6 +178,9 @@ class LanChecker:
 
         if result.details:
             payload["details"] = result.details
+            # Extract temperature for SNMP checks
+            if "temperature" in result.details:
+                payload["temperature"] = result.details["temperature"]
 
         topic = f"lan_checker/{check['id']}/state"
         self.mqtt_client.publish(topic, json.dumps(payload), retain=True)