feat: use sessionKey for bell comparison in pill badges

Update updatePillBell and updateSessionPill to build a viewingKey
that accounts for remote sessions (_viewingRemoteId prefix) and
compare using s.sessionKey || s.name instead of s.name alone.

This prevents false bell suppression when a local session shares a
name with a remote session — the two are now distinguished by their
fully-qualified key (remoteId:name vs plain name).

muxplex/frontend/app.js

@@ -1039,8 +1039,9 @@ function showToast(msg) {
 function updatePillBell() {
   const el = $('session-pill-bell');
   if (!el) return;
+  const viewingKey = _viewingRemoteId ? (_viewingRemoteId + ':' + _viewingSession) : _viewingSession;
   const hasBell = _currentSessions.some(
-    (s) => s.name !== _viewingSession && s.bell && s.bell.unseen_count > 0,
+    (s) => (s.sessionKey || s.name) !== viewingKey && s.bell && s.bell.unseen_count > 0,
   );
   if (hasBell) el.classList.remove('hidden'); else el.classList.add('hidden');
 }
@@ -1872,8 +1873,9 @@ function updateSessionPill(sessions) {
   if (_viewMode !== 'fullscreen') return;
   var pillBell = $('session-pill-bell');
   if (!pillBell) return;
+  var viewingKey = _viewingRemoteId ? (_viewingRemoteId + ':' + _viewingSession) : _viewingSession;
   var othersWithBell = sessions.filter(function(s) {
-    return s.name !== _viewingSession &&
+    return (s.sessionKey || s.name) !== viewingKey &&
       s.bell && s.bell.unseen_count > 0 &&
       (s.bell.seen_at === null || s.bell.last_fired_at > s.bell.seen_at);
   });

muxplex/tests/test_frontend_js.py

@@ -2494,3 +2494,52 @@ def test_device_name_change_updates_document_title() -> None:
     assert "document.title" in body, (
         "bindStaticEventListeners device-name handler must update document.title"
     )
+
+
+# ─── task-4-frontend-session-key-comparison ─────────────────────────────────
+
+
+def test_update_pill_bell_uses_session_key_or_name() -> None:
+    """updatePillBell must compare using sessionKey||name against a viewingKey
+    that accounts for remote sessions (_viewingRemoteId prefix)."""
+    match = re.search(
+        r"function updatePillBell\s*\(\s*\)\s*\{(.*?)\n\}",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "updatePillBell function not found"
+    body = match.group(1)
+    # Must build viewingKey using _viewingRemoteId
+    assert "_viewingRemoteId" in body, (
+        "updatePillBell must reference _viewingRemoteId to build viewingKey"
+    )
+    assert "viewingKey" in body, (
+        "updatePillBell must define a viewingKey variable"
+    )
+    # Must compare using sessionKey || s.name (not just s.name)
+    assert "sessionKey" in body, (
+        "updatePillBell must compare using s.sessionKey || s.name (not just s.name)"
+    )
+
+
+def test_update_session_pill_uses_session_key_or_name() -> None:
+    """updateSessionPill must compare using sessionKey||name against a viewingKey
+    that accounts for remote sessions (_viewingRemoteId prefix)."""
+    match = re.search(
+        r"function updateSessionPill\s*\(\w+\)\s*\{(.*?)\n\}",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "updateSessionPill function not found"
+    body = match.group(1)
+    # Must build viewingKey using _viewingRemoteId
+    assert "_viewingRemoteId" in body, (
+        "updateSessionPill must reference _viewingRemoteId to build viewingKey"
+    )
+    assert "viewingKey" in body, (
+        "updateSessionPill must define a viewingKey variable"
+    )
+    # Must compare using sessionKey || s.name (not just s.name)
+    assert "sessionKey" in body, (
+        "updateSessionPill must compare using s.sessionKey || s.name (not just s.name)"
+    )