init: telegram bot bridging messages to claude sessions

Async Rust bot (teloxide + tokio) that:
- Authenticates users per chat with a passphrase (resets daily at 5am)
- Generates deterministic UUID v5 session IDs from chat_id + date
- Pipes messages to `claude -p --session-id/--resume <uuid>`
- Persists auth and session state to disk across restarts
- Deploys as systemd --user service via `make deploy`

doc/todo.md

@@ -0,0 +1,8 @@
+# TODO
+
+- [ ] Streaming responses — edit message as `ms` output arrives instead of waiting for full completion
+- [ ] Markdown formatting — parse `ms` output and send with TG MarkdownV2
+- [ ] Timeout handling — kill `ms` if it hangs beyond a threshold
+- [ ] Graceful shutdown on SIGTERM
+- [ ] `/reset` command to force new session without waiting for 5am
+- [ ] Rate limiting per chat