feat: support telegram media and artifact delivery

[eorry-bit]

Summary

• support Telegram media messages as Codex input, including cached local attachments and inline text extraction for readable files
• keep Telegram typing indicators alive while Codex is working
• send generated artifacts back to Telegram users, with native photo, video, and audio delivery when possible
• add git-diff fallback artifact detection for both SDK and CLI backends
• show a file list and explanation before sending multiple generated artifacts
• stabilize telegram smoke stderr behavior

Verification

• tsc --noEmit
• eslint
• prettier --check .
• node --import tsx --test tests/handlers.test.ts tests/ptyManager.test.ts
• deployed and restarted user service: codexclaw.service