feat: soundboard, account menu, and call timer

Soundboard: the trigger travels over the WebSocket and every client in the
call plays the clip locally, instead of mixing it into the presser's
microphone or publishing a LiveKit track. No upstream bandwidth, no media
stack changes, and the clip is not degraded by voice processing.

Fan-out uses a new sendToRoomParticipants rather than sendToRoom: the latter
broadcasts a space room to the whole space, which is right for the presence
the sidebar shows and wrong for anything audible. The cooldown is enforced
server-side — a client-side one only slows down people not trying to abuse it,
and a soundboard is the easiest thing here to turn into a weapon. Playing is
open to anyone in the call; deciding what the buttons are needs MANAGE_SPACE.

Account menu: the name in the user bar had cursor-pointer and no handler, so
the interface was already promising a click that did nothing. Offers profile,
status and copy-id — not the Clips or account switching the reference design
shows, which would be dead UI here.

Call timer: startedAt comes from the server, so a late joiner sees the call's
age rather than their own arrival. Empty space rooms are destroyed already,
which is what makes the next call start from zero — no reset logic needed.

packages/server/src/index.ts

@@ -18,6 +18,7 @@ import { livekitRoutes } from './routes/livekit.js';
 import { spotifyRoutes } from './routes/spotify.js';
 import { auditRoutes } from './routes/audit.js';
 import { statsRoutes } from './routes/stats.js';
+import { soundboardRoutes } from './routes/soundboard.js';
 import { closeOrphanedVoiceSessions } from './utils/voiceSessions.js';
 import { socialRoutes } from './routes/social.js';
 import { settingsRoutes } from './routes/settings.js';
@@ -137,6 +138,7 @@ async function main(): Promise<void> {
   await app.register(spotifyRoutes);
   await app.register(auditRoutes);
   await app.register(statsRoutes);
+  await app.register(soundboardRoutes);
   await app.register(socialRoutes);
   await app.register(settingsRoutes);
   await app.register(utilRoutes);