feat(telegram): add /support command with support-desk info reply

Intercept /support in the main bot with a dedicated handler (registered
like /start), replying with a fixed support-desk info message: the
operators' working hours and what to include (a description and, when
possible, screenshots). The reply is Russian or English by the sender's
reported Telegram language, and the command is listed in the bot's
command menu (localized).

Being a dedicated handler, it intercepts /support before the support
relay, so the command line itself is not forwarded into an operator
topic while the user's following description still is.

Update the telegram README and FUNCTIONAL.md (+ _ru mirror).

platform/telegram/README.md

@@ -9,8 +9,9 @@ it. See [`docs/ARCHITECTURE.md`](../../docs/ARCHITECTURE.md) §1/§3/§10/§12/
   validation gRPC API the gateway calls during Telegram auth, on the trusted internal
   network with no VPN. Because it needs no Telegram reachability, **game login stays up
   even when the bot or the bot-link is down**.
-- **`cmd/bot`** (remote) — runs the Bot API long-poll (Mini App launch + `/start`
-  deep-links) and `sendMessage`, the only component reaching the Telegram Bot API. It
+- **`cmd/bot`** (remote) — runs the Bot API long-poll (Mini App launch, `/start`
+  deep-links, the `/support` info reply) and `sendMessage`, the only component reaching
+  the Telegram Bot API. It
   holds **no inbound port**: it dials the gateway over a reverse **mTLS bot-link** and
   executes the send commands the gateway pushes, so its egress can run on a host with
   native Telegram access (a VPN sidecar in the test contour, a separate host in prod).
@@ -49,6 +50,13 @@ Telegram identity to an account from a browser. Both map a rejection to gRPC
   chat" — rather than a dangling "@"). This is otherwise **self-contained**
   — the bot never calls back into the game, so `/start` onboarding works even when the game
   is down.
+- **Support command.** `/support` replies with a fixed support-desk info message — the
+  operators' working hours and what to include (a description and, when possible,
+  screenshots). Like `/start` it answers only in a private chat and is **Russian or
+  English** by the sender's reported language, and it is listed in the bot's command menu
+  (localized, Russian/English). It is a dedicated command handler, so it intercepts
+  `/support` before the support relay below — the command line itself is not forwarded to
+  operators, while the user's following description still is.
 - **Moderated-chat gating.** When `TELEGRAM_CHAT_ID` names a channel's linked discussion
   group, the bot gates who may write there. The group **allows sending by default** (a
   human setting) and the bot only **restricts** — Telegram intersects the chat default with
@@ -76,7 +84,8 @@ Telegram identity to an account from a browser. Both map a rejection to gRPC
   message. State (user→topic map, block list, relayed ids) is a JSON file under
   `TELEGRAM_SUPPORT_STATE_DIR` on a persistent volume — the bot host has no database. The bot must
   be an **administrator** in the group with the **manage-topics** and **delete-messages** rights.
-  The relay is bot-local (no backend, no bot-link) and the user gets no automatic reply.
+  The relay is bot-local (no backend, no bot-link) and a forwarded message gets no automatic
+  reply (the `/support` command above aside).
 - **Promo bot (optional).** When `TELEGRAM_PROMO_BOT_TOKEN` is set, the container also
   runs a **second, standalone** bot whose only job is to answer `/start` with a localized
   message and a button that opens the **main** bot's Mini App. The button is a **URL** to