fix(gateway): pin Telegram DM-topic routing to user's current topic

Topic-mode DM replies were fragmenting one conversation across many sessions: a Reply on a message in another topic delivered Telegram's message_thread_id for *that* topic, and #3206's strip routed plain replies to the lobby. Both pulled the user away from their current session. Fix: when topic mode is on, rewrite source.thread_id to the user's most-recent binding if the inbound id is missing/General or not a known topic. Non-topic-mode users unchanged.

hermes_state.py

@@ -2831,6 +2831,27 @@ class SessionDB:
                 return None
         return dict(row) if row else None
 
+    def list_telegram_topic_bindings_for_chat(
+        self,
+        *,
+        chat_id: str,
+    ) -> List[Dict[str, Any]]:
+        """All Telegram DM topic bindings for one chat, newest first.
+
+        Read-only; returns [] if the bindings table doesn't exist yet
+        (does not trigger the topic-mode migration).
+        """
+        with self._lock:
+            try:
+                rows = self._conn.execute(
+                    "SELECT * FROM telegram_dm_topic_bindings "
+                    "WHERE chat_id = ? ORDER BY updated_at DESC",
+                    (str(chat_id),),
+                ).fetchall()
+            except sqlite3.OperationalError:
+                return []
+        return [dict(row) for row in rows]
+
     def bind_telegram_topic(
         self,
         *,