transcript: fix duplicate copy on multi-device + iOS download hijacking the app

- Duplicate ("Transcript shows two times"): finalizeTranscript had a race — for the
  SAME user on two devices (#12 multi-device), both devices leaving at once each
  passed the subscriber membership check across an await before either removed the
  sub, so both wrote a private transcript. Now the subscriber is CLAIMED
  SYNCHRONOUSLY (subs.delete filter) before any await, so only the first writer wins.
  Verified with a concurrency simulation (2 concurrent leaves -> 1 write).
- iOS download: the /mrec transcript link had no `download` attribute, so WKWebView
  NAVIGATED to the file and loaded it inline with no way back (had to force-quit the
  app). Added download + data-mime so browsers download it and the existing native
  click-interceptor catches it: it now saves to the Files folder and opens in native
  Quick Look (view + its own share/save — into Files or Word) instead of hijacking
  the WebView. recDTO now exposes the recording mime.

Web/server only — no native build needed; live on next app launch.

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

server/calls.js

@@ -32,21 +32,25 @@ async function meetingContext(room) {
 async function finalizeTranscript(room, onlyUserId) {
   const subs = transcriptSubs.get(room); if (!subs || !subs.size) { if (!onlyUserId) { transcriptBuffers.delete(room); transcriptSubs.delete(room); } return; }
   const buf = transcriptBuffers.get(room) || [];
-  const ids = onlyUserId ? (subs.has(onlyUserId) ? [onlyUserId] : []) : [...subs];
+  // CLAIM the subscriber(s) SYNCHRONOUSLY (before any await). Two concurrent finalize calls for the SAME uid —
+  // e.g. the same user's two devices both leaving at once (#12 multi-device) — would otherwise both pass the
+  // membership check during the awaits below and write the transcript TWICE (the "transcript shows two times"
+  // bug). subs.delete() returns true only for the first caller, so the loser claims nothing and writes nothing.
+  const candidates = onlyUserId ? (subs.has(onlyUserId) ? [onlyUserId] : []) : [...subs];
+  const ids = candidates.filter((uid) => subs.delete(uid));
   if (ids.length && buf.length) {
     const ctx = await meetingContext(room);
     const lines = buf.map((s) => { const ts = new Date(s.t); const hh = String(ts.getHours()).padStart(2, '0'), mm = String(ts.getMinutes()).padStart(2, '0'); return '[' + hh + ':' + mm + '] ' + s.speaker + ': ' + s.text; });
     const body = ctx.title + ' — transcript\n' + new Date(buf[0].t).toLocaleString() + '\n\n' + lines.join('\n') + '\n';
     for (const uid of ids) {
       let user = null; try { user = await R.users.byId(uid); } catch (_) {}
-      if (!user) { subs.delete(uid); continue; }
+      if (!user) continue;
       const id = A.id(); const file = 'm_' + id + '.txt';
       try { fs.writeFileSync(path.join(TRANS_DIR, file), body); } catch (e) { continue; }
       // groupId null → private to its creator (see canSeeRec / /mrec auth).
       await R.recordings.create({ id, teamId: user.team_id, room, groupId: null, meetingId: ctx.meetingId, title: ctx.title, kind: 'transcript', file, mime: 'text/plain', size: null, durationMs: null, createdBy: uid, createdByName: user.name || user.email });
-      subs.delete(uid);
     }
-  } else { ids.forEach((uid) => subs.delete(uid)); }
+  }
   if (!subs.size) { transcriptBuffers.delete(room); transcriptSubs.delete(room); } // last subscriber done
 }
 

server/public/home.html

@@ -3229,7 +3229,13 @@ async function nativeSaveFile(url, name, meta){
     e.preventDefault(); e.stopPropagation();                       // never let the WebView navigate to the file
     var P=C.Plugins;
     // Real inline save into the app's Files folder (id comes from /files/<id>; mime refines the subfolder).
-    if(P&&P.Filesystem){ nativeSaveFile(href, a.getAttribute('download')||'', { mime:a.getAttribute('data-mime')||'' }); return; }
+    if(P&&P.Filesystem){
+      var isRec=/\/mrec\//.test(href); var dn=a.getAttribute('download')||'';
+      // recordings/transcripts: after saving, OPEN in native Quick Look (view + its own share/save — e.g. into
+      // Files or Word) instead of the WebView loading the file inline with no way back.
+      nativeSaveFile(href, dn, { mime:a.getAttribute('data-mime')||'' }).then(function(){ if(isRec){ var rid=String(href).split('?')[0].split('/').pop(); var rec=bzLibGet(rid); if(rec) bzOpenFile(rec, dn); } });
+      return;
+    }
     var isImg = /\.(png|jpe?g|gif|webp|heic|heif|bmp|svg)(\?|#|$)/i.test(href) || !!a.closest('.lightbox');
     toast(isImg ? 'Press and hold the image, then tap "Save to Photos".' : 'Saving files needs the latest app update.');
   }, true); // capture phase so it wins over the lightbox / bubble handlers
@@ -5077,7 +5083,7 @@ async function loadScheduledMeetings(){
     +'<div class="si-meta">'+meta.join(' · ')+'</div>'
     +(m.description?'<div class="si-desc">'+pEsc(m.description)+'</div>':'')
     +(m.invited&&m.invited.length?'<div class="si-invited" title="'+pEsc(m.invited.join(', '))+'">'+ic('users',12)+' '+pEsc(m.invited.slice(0,3).join(', '))+(m.invited.length>3?(' +'+(m.invited.length-3)):'')+'</div>':'')
-    +(m.recordings&&m.recordings.length?'<div class="si-recs">'+m.recordings.map(r=>'<a class="rec-dl '+(r.kind==='video'?'vid':'txt')+'" href="'+pEsc(r.url)+'" title="Download '+(r.kind==='video'?'recording':'transcript')+'">'+ic('download',14)+'<span>'+(r.kind==='video'?'Recording':'Transcript')+'</span>'+(r.kind==='video'&&r.durationMs?'<span class="rd-dur">'+fmtElapsed(r.durationMs)+'</span>':'')+'</a>').join('')+'</div>':'')+'</div>'
+    +(m.recordings&&m.recordings.length?'<div class="si-recs">'+m.recordings.map(r=>{ var isVid=r.kind==='video'; var _dn=String(m.title||'Meeting').replace(/[\/\\:*?"<>|]+/g,'_')+(isVid?' recording':' transcript')+(isVid?(/mp4/.test(r.mime||'')?'.mp4':'.webm'):'.txt'); return '<a class="rec-dl '+(isVid?'vid':'txt')+'" href="'+pEsc(r.url)+'" download="'+pEsc(_dn)+'" data-mime="'+pEsc(r.mime||(isVid?'video/webm':'text/plain'))+'" title="Download '+(isVid?'recording':'transcript')+'">'+ic('download',14)+'<span>'+(isVid?'Recording':'Transcript')+'</span>'+(isVid&&r.durationMs?'<span class="rd-dur">'+fmtElapsed(r.durationMs)+'</span>':'')+'</a>'; }).join('')+'</div>':'')+'</div>'
     +'<div class="si-actions">'
     +((m.status!=='past'&&!cancelled)?'<button class="iconbtn copylink" data-link="'+pEsc(m.link||'')+'" title="Copy invite link" aria-label="Copy invite link">'+ic('link',14)+'</button>':'')
     +((m.status!=='past'&&!cancelled&&canStart)?'<button class="btn sm join" data-code="'+pEsc(m.roomCode)+'">'+(m.status==='running'?'Join':'Start')+'</button>':'')

server/routes.js

@@ -1320,7 +1320,7 @@ route('GET', '/api/meetings', async (req, res) => {
   // Attach recordings/transcripts. A recording is visible to its creator, group members, or people
   // who can see the scheduled meeting it belongs to. Recordings not tied to a listed meeting become
   // their own "Past meeting" entry (group calls show the group name).
-  const recDTO = (r) => ({ id: r.id, kind: r.kind, url: '/mrec/' + r.id, createdAt: r.created_at, durationMs: r.duration_ms, size: r.size, by: r.created_by_name });
+  const recDTO = (r) => ({ id: r.id, kind: r.kind, url: '/mrec/' + r.id, mime: r.mime || '', createdAt: r.created_at, durationMs: r.duration_ms, size: r.size, by: r.created_by_name });
   const canSeeRec = async (r) => {
     if (r.kind === 'transcript') return r.created_by === u.id; // transcripts are private to their owner
     if (r.created_by === u.id) return true;