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/index.html

@@ -15,6 +15,11 @@
             <span id="updated" class="muted">loading…</span>
         </div>
 
+        <div class="card" id="deploywarn-card" style="display:none">
+            <h3>Deploy Warnings</h3>
+            <div id="deploywarn"></div>
+        </div>
+
         <div class="card">
             <h3>Access Points</h3>
             <div id="ap"></div>
@@ -45,6 +50,14 @@
             <div id="starlink"></div>
         </div>
 
+        <div class="card">
+            <div class="card-head">
+                <h3>Wi-Fi Networks</h3>
+                <button id="wifi-scan" class="btn">Scan</button>
+            </div>
+            <div id="wifi"><p class="muted">Click Scan to search for networks.</p></div>
+        </div>
+
         <div class="card">
             <h3>WAN / Uplinks</h3>
             <table>