polish(web): clear device lists on permission revoke; document probe-constraint omission

packages/web/src/hooks/useAudioDevices.ts

@@ -139,7 +139,11 @@ export function useAudioDevices(): UseAudioDevicesResult {
 
   // Enumerate when permission grants; refresh on devicechange.
   useEffect(() => {
-    if (permState !== 'granted') return;
+    if (permState !== 'granted') {
+      setInputs([]);
+      setOutputs([]);
+      return;
+    }
     enumerate();
     const onChange = () => { enumerate(); };
     navigator.mediaDevices.addEventListener('devicechange', onChange);

packages/web/src/hooks/useLiveKit.ts

@@ -436,6 +436,10 @@ export function useLiveKit() {
       let copy = 'Microphone could not be restored';
 
       try {
+        // Probe is intentionally constraint-free — we want to know whether the
+        // device is reachable, not whether full voice constraints succeed. Adding
+        // constraints here would create probe-vs-acquire skew (probe might fail
+        // for a constraint that AudioManager would have negotiated around).
         const probe = await navigator.mediaDevices.getUserMedia({
           audio: deviceId === 'default' ? true : { deviceId: { exact: deviceId } },
         });