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>

cockpit/vanrouter/vanrouter.css

@@ -23,3 +23,7 @@ th { color: #6a6e73; font-weight: 600; }
 .active-wan { font-weight: 700; color: #0066cc; }
 .btn { margin-left: 6px; padding: 3px 10px; cursor: pointer; }
 .btn[disabled] { cursor: default; opacity: 0.5; }
+#deploywarn-card { border-color: #e08a00; }
+.warn-list { margin: 0; padding-left: 20px; }
+.warn-list li { background: #f5d9a8; color: #5f4414; border-radius: 4px;
+                padding: 4px 8px; margin: 4px 0; list-style: none; margin-left: -20px; }