Native calls: open the REAL meeting window (join the mesh), drop the bespoke overlay

The custom call overlay was wrong — the native call must use the app's actual
meeting UI. Fix: a native call now JOINS the mesh room like any participant, so
the caller/callee tiles, roster, mute state and the whole answer/end lifecycle
run through the existing (tested) meeting code. The only native-specific bit is
meetNative=true → the WebView does NOT open its own SFU media connection (the
plugin already owns this identity's one LiveKit connection); mic/hang-up bridge
to the plugin. This fixes, via existing server code, all the reported bugs:
- "no meeting window" → the real meeting window opens on answer/outgoing.
- "caller stuck Ringing after pickup" → mesh peer-join clears the waiting tile
  and finishMeetingJoin marks the call answered.
- "call still running after the other side hung up" → mesh leave ends the DM
  for both (signaling leaveMeeting); plus an idempotent endDmCallByRoom backup
  kicks a stuck peer when the ending side's WebSocket is down.
- "accept on one device doesn't stop the other" → markDmAnswered (fired on mesh
  join) emits call-taken to the user's other sockets; deliverLocal fans to all.
- "second-device accept wins / collision" → the other device's ring is dismissed
  so it can't double-join the same identity.

home.html: enterMeeting(code, audioOnly, {native, uuid}); skip sfuConnect when
native; toggleMic->plugin; toggleCam blocked (video is the next phase); leave ->
callkitEnd (guarded against the plugin's endCall re-firing).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/calls.js

@@ -137,6 +137,11 @@ async function endDmCallByRoom(room, silent) {
   if (!call) return;
   if (call.ringTimer) { try { clearTimeout(call.ringTimer); } catch (_) {} }
   if (call.historyId && call.teamId) { try { await R.scheduledMeetings.end(call.historyId, call.teamId); } catch (_) {} } // mark history past
+  // A native side that ends the call (POST /api/calls/end) may have a dropped WebSocket, so the OTHER party
+  // can be left sitting in the mesh meeting "still in the call". Close their window. Idempotent: when this
+  // runs from the mesh emptying normally, the room is already gone → no-op (so it never double-ends).
+  const stuck = meetingRooms.get(room);
+  if (stuck) { for (const [, p] of stuck) { if (p.ws && p.ws.readyState === 1) { try { p.ws.send(JSON.stringify({ type: 'meeting-ended' })); } catch (_) {} p.ws._meetingRoom = null; } } meetingRooms.delete(room); }
   // Activity line: a duration ONLY if the call was answered; otherwise "Missed call" (#7/#9).
   if (!silent) try {
     const mid = A.id(); const body = call.answered ? ('📞 Call ended · ' + fmtDur(now() - (call.answeredAt || call.startedAt))) : '📞 Missed call';