feat(call): ask before joining when your usual mic / headphones are missing (#121)

The fork now checks, before joining (lotusDeviceCheck=1), that the mic /
output the user last picked are plugged in. When one is missing it asks
us (io.lotus.device_missing): "Your usual microphone isn't connected.
Arctis 7 isn't connected. Join with Laptop Mic instead?" [Join anyway]
[Cancel]. Join anyway isn't asked again this session for the same
device(s); Cancel closes the call before it starts. A device lost during
a call is a toast ("Arctis 7 disconnected — now using Laptop Mic").

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/components/CallEmbedProvider.tsx

@@ -52,6 +52,7 @@ import { useCallEndedToast } from '../hooks/useCallEndedToast';
 import { useCallRejoin } from '../hooks/useCallRejoin';
 import { usePttHaptics } from '../hooks/usePttHaptics';
 import { useScreenshareNotices } from '../hooks/useScreenshareNotices';
+import { ExpectedDevicesPrompt } from '../features/call/ExpectedDevicesPrompt';
 import { useCallAnnouncements } from '../hooks/useCallAnnouncements';
 import { useMutedTalkWarning } from '../hooks/useMutedTalkWarning';
 import { callAnnouncementAtom } from '../state/callAnnouncement';
@@ -858,7 +859,14 @@ function CallUtils({ embed, joined }: { embed: CallEmbed; joined: boolean }) {
     };
   }, [joined]);
 
-  return null;
+  return (
+    <ExpectedDevicesPrompt
+      embed={embed}
+      onCancel={() => {
+        setCallEmbed(undefined);
+      }}
+    />
+  );
 }
 
 /**