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>

failover/sync-usb-backup.sh

@@ -15,6 +15,11 @@ set -euo pipefail
 
 USB_ROOT_PART=/dev/sda2
 MOUNT_POINT=/mnt/usb-backup-root
+MOUNT_POINT=10.42.1.44:/media/andreas/writable-nvme
+
+
+[[ "$MOUNT_POINT" == *":"* ]]
+LOCAL_MOUNT=$?
 
 root_src=$(findmnt -no SOURCE /)
 if [ "$root_src" = "$USB_ROOT_PART" ]; then
@@ -22,21 +27,23 @@ if [ "$root_src" = "$USB_ROOT_PART" ]; then
     exit 1
 fi
 
-mkdir -p "$MOUNT_POINT"
-mounted_here=0
-if ! mountpoint -q "$MOUNT_POINT"; then
-    mount "$USB_ROOT_PART" "$MOUNT_POINT"
-    mounted_here=1
-else
-    mount -o remount,rw "$MOUNT_POINT"
-fi
+if [ $LOCAL_MOUNT -eq 1 ]; then
+	mkdir -p "$MOUNT_POINT"
+	mounted_here=0
+	if ! mountpoint -q "$MOUNT_POINT"; then
+	    mount "$USB_ROOT_PART" "$MOUNT_POINT"
+	    mounted_here=1
+	else
+	    mount -o remount,rw "$MOUNT_POINT"
+	fi
 
-cleanup() {
-    if [ "$mounted_here" -eq 1 ]; then
-        umount "$MOUNT_POINT"
-    fi
-}
-trap cleanup EXIT
+	cleanup() {
+	    if [ "$mounted_here" -eq 1 ]; then
+	        umount "$MOUNT_POINT"
+	    fi
+	}
+	trap cleanup EXIT
+fi
 
 # rsync exit 24 ("partial transfer due to vanished source files") is expected on a
 # live root — files like container shm sockets or in-progress logs routinely disappear