deploy: hardware-instance templating, wlan0 boot watchdog, deploy-time warnings in Cockpit

- deploy.conf templates interface names/USB IDs (@TOKEN@ substitution) across
  ap/* configs so a dongle swap only needs deploy.conf edited, not the repo
  configs themselves; drops ap/rtw88.conf (old 2.4GHz dongle retired for the
  DWA-171, which needs no such power-save override).
- failover/van-wlan-watchdog: recovers wlan0 from NM's post-boot no-secrets
  wedge (a boot-time supplicant race, not a real credential failure).
- deploy.sh: warn() collects dependency/config warnings (missing python3-gps,
  python3-paho-mqtt, mobile-broadband-provider-info, grpcurl, gpsd; netplan
  drift; unedited example configs) into /var/lib/vanlink/deploy-warnings.json,
  rendered as an amber Cockpit card so they're visible without reading deploy
  output.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

ap/van-ap-unmanaged.conf

@@ -2,4 +2,4 @@
 # The AP wlans (5GHz + 2.4GHz) and the wired LAN ports (USB dongle + onboard
 # eth0) are all owned by systemd-networkd/hostapd (bridged into br0), so
 # NetworkManager must not touch them.
-unmanaged-devices=interface-name:wlxc83a35a4ee55;interface-name:wlxd8ec5e2faa8c;interface-name:enx00e04c331140;interface-name:eth0
+unmanaged-devices=interface-name:@WIFI_5G_IFACE@;interface-name:@WIFI_2G_IFACE@;interface-name:@LAN_USB_IFACE@;interface-name:eth0