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/internal/bot/bot.go

@@ -1,6 +1,7 @@
 // Package bot wraps the Telegram Bot API client (github.com/go-telegram/bot): it
 // runs the long-poll update loop — replying to /start (with an optional deep-link
-// payload) and any other message with a Mini App launch button — and sends the
+// payload), to /support with the support-desk info message, and to any other message
+// with a Mini App launch button — and sends the
 // notification and admin messages the connector requests. The bot token lives only
 // in this process.
 package bot
@@ -136,6 +137,7 @@ func New(cfg Config, log *zap.Logger) (*Bot, error) {
 	opts := []tgbot.Option{
 		tgbot.WithDefaultHandler(t.handleUpdate),
 		tgbot.WithMessageTextHandler("/start", tgbot.MatchTypePrefix, t.handleStart),
+		tgbot.WithMessageTextHandler("/support", tgbot.MatchTypePrefix, t.handleSupport),
 	}
 	if t.supportEnabled() {
 		t.supportLocks = newKeyedMutex()
@@ -186,11 +188,26 @@ func New(cfg Config, log *zap.Logger) (*Bot, error) {
 // Run sets the bot commands and the Mini App menu button, then blocks on the
 // long-poll update loop until ctx is cancelled.
 func (t *Bot) Run(ctx context.Context) {
+	// Command menu: the default (fallback) list is English; a Russian-scoped list
+	// localises the labels for ru clients. A language scope replaces the whole list, so
+	// it repeats /start with its own Russian label.
 	if _, err := t.api.SetMyCommands(ctx, &tgbot.SetMyCommandsParams{
-		Commands: []models.BotCommand{{Command: "start", Description: "Open Scrabble"}},
+		Commands: []models.BotCommand{
+			{Command: "start", Description: "Play Scrabble"},
+			{Command: "support", Description: "Contact the administration"},
+		},
 	}); err != nil {
 		t.log.Warn("set commands failed", zap.Error(err))
 	}
+	if _, err := t.api.SetMyCommands(ctx, &tgbot.SetMyCommandsParams{
+		LanguageCode: "ru",
+		Commands: []models.BotCommand{
+			{Command: "start", Description: "Играть в «Эрудита»"},
+			{Command: "support", Description: "Связаться с администрацией"},
+		},
+	}); err != nil {
+		t.log.Warn("set ru commands failed", zap.Error(err))
+	}
 	if _, err := t.api.SetChatMenuButton(ctx, &tgbot.SetChatMenuButtonParams{
 		MenuButton: models.MenuButtonWebApp{
 			Type:   models.MenuButtonTypeWebApp,