Consolidate chat timeline events + auto-end inactive sessions

Timeline consolidation:
- Replace multiple LIVE_CHAT_STARTED/ENDED events with single LIVE_CHAT_SUMMARY
- Show total duration accumulated across all sessions
- Display session count (e.g., "23min 15s total - 3 sessoes")
- Show "Ativo" badge when session is active

Auto-end inactive chat sessions:
- Add cron job running every minute to check inactive sessions
- Automatically end sessions after 5 minutes of client inactivity
- Mark auto-ended sessions with "(encerrado por inatividade)" flag

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

convex/crons.ts

@@ -33,4 +33,12 @@ crons.interval(
   {}
 )
 
+// Encerrar sessoes de chat inativas por mais de 5 minutos (sempre ativo)
+crons.interval(
+  "auto-end-inactive-chat-sessions",
+  { minutes: 1 },
+  api.liveChat.autoEndInactiveSessions,
+  {}
+)
+
 export default crons