Add read-only MG4 ADB status collector

web/src/App.tsx

@@ -322,6 +322,17 @@ function StatusContent({ status }: { status: SystemStatus }) {
   const temperature = status.cpu.temperatureCelsius.available
     ? `${status.cpu.temperatureCelsius.value.toFixed(1)}°C`
     : "Unavailable";
+  const headUnitLabel = status.headUnit.available
+    ? status.headUnit.value.identity.model.available
+      ? status.headUnit.value.identity.model.value
+      : "Connected"
+    : status.headUnit.state === "unauthorized"
+      ? "Authorization required"
+      : status.headUnit.state === "disabled"
+        ? "Not configured"
+        : status.headUnit.state === "offline"
+          ? "Offline"
+          : "Unavailable";
 
   return (
     <div className="status-layout">
@@ -348,6 +359,7 @@ function StatusContent({ status }: { status: SystemStatus }) {
         <div><span>Operating system</span><strong>{status.operatingSystem}</strong></div>
         <div><span>Processor</span><strong>{status.cpu.model}</strong></div>
         <div><span>Wi-Fi detail</span><strong>{status.network.wifi.available ? status.network.wifi.value : status.network.wifi.reason}</strong></div>
+        <div><span>MG4 head unit</span><strong title={status.headUnit.available ? "ADB connected" : status.headUnit.reason}>{headUnitLabel}</strong></div>
       </section>
     </div>
   );