fix: prevent infinite message replay on container timeout (#164)

Container timeout and idle timeout both fire at 30min, racing the
graceful shutdown. The hard kill returns error status, rolling back
the message cursor even though output was already sent — causing
duplicate messages indefinitely.

- Grace period: hard timeout is now IDLE_TIMEOUT + 30s minimum
- Timeout after output resolves as success (idle cleanup, not failure)
- Don't roll back cursor if output was already sent to user
- Remove src/telegram.ts and config vars (added to PR #156 by mistake)
- Add typecheck step to CI workflow
- Add container-runner timeout behavior tests

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/config.ts

@@ -1,12 +1,6 @@
 import path from 'path';
 
 export const ASSISTANT_NAME = process.env.ASSISTANT_NAME || 'Andy';
-export const TELEGRAM_BOT_TOKEN = process.env.TELEGRAM_BOT_TOKEN || '';
-export const TELEGRAM_ONLY = process.env.TELEGRAM_ONLY === 'true';
-export const TELEGRAM_BOT_POOL = (process.env.TELEGRAM_BOT_POOL || '')
-  .split(',')
-  .map((t) => t.trim())
-  .filter(Boolean);
 export const POLL_INTERVAL = 2000;
 export const SCHEDULER_POLL_INTERVAL = 60000;