feat: add multi-account support

[dsvetlov]

Summary

• Support multiple Telegram accounts simultaneously via label-suffixed env vars (TELEGRAM_SESSION_STRING_WORK, _PERSONAL, etc.)
• Single-account configs remain fully backward-compatible — zero changes needed
• Read-only tools fan out to all accounts when account is omitted; write tools require explicit account
• New list_accounts tool for account discovery
• All 93 tools gain @with_account decorator and account parameter
• Concurrent client startup via asyncio.gather
• Updated session string generator with optional label prompt

Test plan

• Single-account mode: existing .env with one TELEGRAM_SESSION_STRING works identically to before
• Multi-account mode: two labeled sessions, verify list_accounts returns both
• Read-only fan-out: get_chats() without account returns results from all accounts with [label] prefix
• Write guard: send_message() without account in multi-mode returns error listing available accounts
• Write with account: send_message(account="work", ...) sends from correct account
• Session generator: label prompt works, outputs correct env var name

🤖 Generated with Claude Code

[dsvetlov]

Hey @chigwell — friendly ping on this one.

Not an April Fools joke, for the record :) I've been running this branch off my fork since April 1st with two Telegram accounts (work + personal) and everything has been working great — no bugs surfaced so far.

Happy to address anything on your end: code style, test coverage, API design, naming — whatever would help get this merged. And if you feel multi-account support just doesn't fit the direction you want mcp-telegram to go, that's a totally valid answer too — just let me know and I'll keep maintaining it on the fork.

Thanks!

[chigwell]

Hi @dsvetlov,
Thank you for your contribution. Could you please resolve the pull request conflicts? Also, could you remove the openspec folder from this PR? Thank you.

[dsvetlov]

@chigwell done — both asks addressed:

1. Removed openspec/ (commit 58f225d) — those were local spec-driven planning artifacts that shouldn't have been committed.
2. Resolved conflicts with main (commit b8fdcfe + black formatting in d295d6c) — merged in all the upstream changes since April 1st.

The merge required a bit more than a straight conflict resolution because several things landed on main that interact with multi-account:

• ensure_connected() / _force_reconnect() (from fix: robust ensure_connected() — verify with ping, force reconnect on stale TCP #98) now accept an explicit client parameter and fall back to the single-account client when called without one. _last_conn_verified is now keyed per-client.
• _main() cleanup on shutdown now disconnects all configured clients via asyncio.gather.
• 16 new tool functions from upstream (send_scheduled_message, get_scheduled_messages, delete_scheduled_message, edit_chat_about, set_default_chat_permissions, toggle_slow_mode, edit_admin_rights, delete_chat_history, delete_messages_bulk, unpin_all_messages, get_full_user, get_full_chat, send_contact, get_common_chats, get_message_read_by, get_message_link) got wrapped with @with_account + the account parameter so they work in both single- and multi-account modes.
• list_chats merged both additions cleanly — it now has both account (from this PR) and with_about (from feat: add with_about to list_chats for dispatch disambiguation #106).

All three CI checks pass ✅. Let me know if you want anything else tweaked.

[dsvetlov]

@chigwell gentle ping — both items are addressed and CI is green. Could you take another look when you have a minute? Thanks!