docs(telegram): document Bot API 10.0 guest mode media delivery

website/docs/user-guide/messaging/telegram.md

@@ -1069,6 +1069,32 @@ With `guest_mode: true`, a message from a non-allowlisted group is processed **o
 
 DMs and allowlisted groups behave exactly as before.
 
+### Native guest replies (Bot API 10.0)
+
+Telegram's Bot API 10.0 added **Guest Bots**: a bot can receive an `@mention` from a group it has never joined via a `guest_message` update, and reply to it exactly once via `answerGuestQuery`. This is the delivery mechanism behind `guest_mode: true` above — when your bot's Telegram client library and Bot API version support it, Hermes uses it automatically. There's no separate config flag; it's covered by the same `guest_mode: true` setting.
+
+**How a reply looks to the user:**
+
+1. Someone @mentions the bot in a group it isn't a member of.
+2. The bot immediately posts a placeholder (a short "⏳ Thinking..." style message) — guest replies are one-shot and Telegram expects a fast acknowledgement.
+3. Once the agent finishes processing, that placeholder is edited in place with the final answer.
+
+**Media in guest replies.** A `guest_message` reply can only carry text and buttons — Telegram doesn't allow pushing a file directly into it. If the agent's reply includes a file (image, audio, video, document), Hermes instead edits the placeholder to a **"✅ Ready — tap to receive"** button. Tapping it sends a fresh `guest_message` carrying a one-time delivery token; the bot answers that one with the actual file, delivered inline as a cached-file result. This two-step dance is purely a side effect of the one-shot `answerGuestQuery` constraint — from the user's side it's just "tap the button to get the file."
+
+This requires one more setting: a home chat the bot **is** a member of, used to stage the file before Telegram will let it be reused as a cached inline result. This can be a group/channel (negative id) or simply your own private DM with the bot (positive id) — any chat the bot can already message works.
+
+```bash
+TELEGRAM_HOME_CHANNEL="123456789"   # e.g. your own DM with the bot, or a group/channel id
+```
+
+Without `TELEGRAM_HOME_CHANNEL` set, guest-mode media delivery falls back to a text-only reply (no button, no file).
+
+**Limitations:**
+
+- Delivery tokens expire **10 minutes** after the button is posted. Tapping "tap to receive" after that shows an error instead of the file — just ask again.
+- Tapping the same button more than once re-delivers the file rather than erroring, as long as it's still within the 10-minute window.
+- Same as plain `guest_mode`: no session stickiness. Every guest interaction — including tapping the deliver button — is its own one-shot exchange; the bot doesn't remember prior guest turns between mentions.
+
 ## Slash Command Access Control
 
 By default, every allowed user can run every slash command. To split your allowlist into **admins** (full slash command access) and **regular users** (only commands you explicitly enable), add `allow_admin_from` and `user_allowed_commands` to the platform's `extra` block: