fix: follow-up for salvaged PR #22263

- Restore allowed_chats gate before thread_id check so ignored_threads
  applies universally (even to guest mentions).
- Compute _message_mentions_bot once in _should_process_message to
  eliminate redundant second entity scan when guest_mode=true and the
  message does not mention the bot.
- Remove redundant _is_group_chat from _is_guest_mention (caller already
  verified the message is a group chat).
- Update _telegram_allowed_chats docstring to note guest_mode exception.
- Add test coverage: bot_command entity, text_mention entity,
  caption_entities, and ignored_threads + guest_mode interaction.
- Add nik1t7n to AUTHOR_MAP.

tests/gateway/test_telegram_group_gating.py

@@ -186,6 +186,23 @@ def test_guest_mode_defaults_to_false_for_allowed_chat_bypass():
     assert adapter._should_process_message(mentioned) is False
 
 
+def test_guest_mode_mention_dropped_in_ignored_thread():
+    """A guest mention in an ignored thread is still dropped — thread gate runs first."""
+    adapter = _make_adapter(
+        require_mention=True,
+        allowed_chats=["-200"],
+        guest_mode=True,
+        ignored_threads=[42],
+    )
+    mentioned = _group_message(
+        "hi @hermes_bot",
+        chat_id=-201,
+        entities=[_mention_entity("hi @hermes_bot")],
+        thread_id=42,
+    )
+    assert adapter._should_process_message(mentioned) is False
+
+
 def test_ignored_threads_drop_group_messages_before_other_gates():
     adapter = _make_adapter(require_mention=False, free_response_chats=["-200"], ignored_threads=[31, "42"])