docs: update docs for Telegram integration

TODO.md

@@ -88,10 +88,23 @@ is preserved in git history for reference.
 - [x] TeamsBot + TeamsMessage (duck-typed with IRC Message)
 - [x] HMAC-SHA256 webhook validation
 - [x] Permission tiers via AAD object IDs
+- [x] Route `send()` through SOCKS5 proxy (bug fix)
 - [ ] Adaptive Cards for richer formatting
 - [ ] Graph API integration for DMs
 - [ ] Teams event handlers (member join/leave)
 
+## Telegram
+
+- [x] Telegram adapter via long-polling (no SDK)
+- [x] TelegramBot + TelegramMessage (duck-typed with IRC Message)
+- [x] All HTTP through SOCKS5 proxy
+- [x] Message splitting at 4096-char limit
+- [x] @botusername suffix stripping in groups
+- [x] Permission tiers via user IDs
+- [ ] Inline keyboard support for interactive replies
+- [ ] Markdown/HTML formatting mode toggle
+- [ ] Webhook mode (for setWebhook instead of getUpdates)
+
 ## Testing
 
 - [x] Plugin command unit tests (encode, hash, dns, cidr, defang)