Fix watchdog timeout and MQTT connectivity issues

Problem: R5C spontaneously rebooted due to hardware watchdog timeout
Cause 1: van-gps-owntracks in infinite restart loop (MQTT connect failed)
Cause 2: mosquitto only listening on localhost, so clients couldn't connect
Solution:
- Add restart limits to van-gps-owntracks and van-li3-battery services
  (max 3 restarts per 5 minutes prevents infinite restart loops)
- Configure mosquitto to listen on all interfaces (0.0.0.0:1883)
- Deploy mosquitto listener config via deploy.sh
- Restart mosquitto during deploy to apply config changes

This prevents the system from hitting the 11-second hardware watchdog timeout
when services crash and systemd auto-restarts them indefinitely.

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

router-status/mosquitto-listener.conf

@@ -0,0 +1,4 @@
+# Van Router MQTT broker configuration
+# Listen on all interfaces for local network access (clients on br0, ZeroTier, etc.)
+listener 1883
+protocol mqtt

router-status/van-gps-owntracks-restart-limit.conf

@@ -0,0 +1,6 @@
+# Restart limit for van-gps-owntracks to prevent watchdog timeout
+# Allows max 3 restarts per 5 minutes; after that, the service stays failed
+# (systemd will not keep restarting it indefinitely)
+[Service]
+StartLimitIntervalSec=300
+StartLimitBurst=3