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).

docs/FUNCTIONAL.md

@@ -407,9 +407,11 @@ unanswered reply. Guests cannot send feedback (the entry is hidden). A player th
 barred from feedback (a role, not a full account block) sees the send control disabled.
 
 ### Telegram support chat
-A user can also reach the operators straight from the Telegram bot: anything they send the bot
-other than `/start` — text, a photo, a voice message, a file — is forwarded into the operators'
-private support group, grouped into a per-user thread. The user sees no automatic reply; an
+A user can also reach the operators straight from the Telegram bot. The `/support` command replies
+with the support desk's working hours and what to include (a description and, when possible,
+screenshots). Anything else they send the bot other than `/start` — text, a photo, a voice message,
+a file — is forwarded into the operators' private support group, grouped into a per-user thread. The
+user sees no automatic reply to a forwarded message; an
 operator answers from that thread and the bot delivers the answer back as an ordinary bot message,
 so to the user it is a quiet one-to-one conversation. Operators can block a user (the bot then
 silently ignores their messages) or clear a thread's messages. This is independent of the in-app