fix(telegram): accept /cmd@botname from bot menu in groups

Telegram groups emit a single bot_command entity covering the whole
/cmd@botname span with no accompanying mention entity, so the existing
mention gate in _message_mentions_bot dropped slash commands sent via
the bot-menu autocomplete whenever require_mention is enabled.

Recognise bot_command entities whose @botname suffix matches the bot
username (case-insensitive) as a direct mention, and keep rejecting
commands addressed at other bots. Fixes #15415.

gateway/platforms/telegram.py

@@ -2353,6 +2353,26 @@ class TelegramAdapter(BasePlatformAdapter):
                     user = getattr(entity, "user", None)
                     if user and getattr(user, "id", None) == bot_id:
                         return True
+                elif entity_type == "bot_command" and expected:
+                    # Telegram's official group-disambiguation form for slash
+                    # commands (``/cmd@botname``) is emitted as a single
+                    # ``bot_command`` entity covering the whole span — there
+                    # is no accompanying ``mention`` entity. Treat it as a
+                    # direct address to this bot when the ``@botname`` suffix
+                    # matches. This is the form Telegram's own command menu
+                    # autocomplete produces in groups, so dropping it at the
+                    # mention gate would break /new, /reset, /help, ... for
+                    # every group that has ``require_mention`` enabled (#15415).
+                    offset = int(getattr(entity, "offset", -1))
+                    length = int(getattr(entity, "length", 0))
+                    if offset < 0 or length <= 0:
+                        continue
+                    command_text = source_text[offset:offset + length]
+                    at_index = command_text.find("@")
+                    if at_index < 0:
+                        continue
+                    if command_text[at_index:].strip().lower() == expected:
+                        return True
         return False
 
     def _message_matches_mention_patterns(self, message: Message) -> bool: