feat(call): Discord-style polish pass (groups A-C)

A — Call core:
- Deafen now implies mute + remembers pre-deafen mic state so un-deafen
  restores it (Discord-parity). Peers still see the headphones-off +
  mic-off badges in sync via the existing data-channel broadcast.
- Self-join sound fires on the local peer's r.connect() too, not just
  on remote ParticipantConnected, so the user gets the "I'm in" cue.
- New CallState.reconnecting holds the UI steady when LiveKit drops the
  signaling socket and retries; duration keeps ticking, status label
  switches to "Verbinde neu…". Full teardown only on terminal
  Disconnected (after LK gives up).
- joinActiveCall falls back to connected after 5s if no peer arrived —
  avoids hanging in "Verbinde…" when peers left the room mid-rejoin.

B — Ringtone:
- Oscillator base gain up (incoming 0.22 -> 0.4, outgoing 0.14 -> 0.22)
  so the default pattern survives laptop speakers + background music.
- New ringtoneVolume slider in Settings, default 0.9, live-applies to
  both the oscillator fallback and the custom-file <audio> element.

C — Participant tile:
- Split the speaking indicator: video tiles get the emerald border +
  inset glow; audio tiles rely on the existing avatar pulse. No more
  double-chrome when someone talks in grid/focus view.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/desktop/src/components/InCallPanel.tsx

@@ -99,6 +99,7 @@ export function InCallPanel({ conversation }: Props) {
   const active =
     (state.kind === 'connected' ||
       state.kind === 'connecting' ||
+      state.kind === 'reconnecting' ||
       state.kind === 'outgoing') &&
     state.conversationId === conversation.id;
   if (!active) return null;
@@ -117,6 +118,9 @@ export function InCallPanel({ conversation }: Props) {
     remoteSharerIds: new Set(remoteScreenShares.map((s) => s.participantId)),
   });
 
+  // Duration keeps ticking during reconnecting so the user sees the call is
+  // still alive — but the status label below takes precedence in the header
+  // so the "Verbinde neu…" message is prominent, not buried under the timer.
   const duration =
     state.kind === 'connected'
       ? <LiveDuration startedAt={state.startedAt} />
@@ -127,9 +131,11 @@ export function InCallPanel({ conversation }: Props) {
       ? t('app:call.outgoing_ringing')
       : state.kind === 'connecting'
         ? t('app:call.connecting')
-        : remoteParticipants.length === 0
-          ? t('app:call.waiting_for_peers', { defaultValue: 'Warte auf andere…' })
-          : t('app:call.connected');
+        : state.kind === 'reconnecting'
+          ? t('app:call.reconnecting', { defaultValue: 'Verbinde neu…' })
+          : remoteParticipants.length === 0
+            ? t('app:call.waiting_for_peers', { defaultValue: 'Warte auf andere…' })
+            : t('app:call.connected');
 
   // A screen-share tile becomes the auto-focus target when no one explicitly
   // picked a tile yet. Focus ids now use Tile.id (kind-prefixed) so we can