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>

ap/10-van-ap.network.bak

@@ -0,0 +1,12 @@
+[Match]
+Name=@WIFI_5G_IFACE@
+
+[Link]
+RequiredForOnline=no
+
+# No IP here: the AP wlan is a member of br0, which carries the 10.42.0.1 gateway.
+# hostapd adds this interface to br0 (bridge=br0) after it puts the radio into AP
+# mode — networkd must NOT enslave it (a station-mode wlan can't be bridged), so
+# this file only brings the link up.
+[Network]
+ConfigureWithoutCarrier=yes