feat: Re-rename DM rooms after 5min gap for new conversation topics

Matrix reuses a single DM room per user pair, so 'new' DMs jump
back to the old thread. Now the bot re-renames the room if >5min
has passed since the last rename, reflecting the new topic.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bot.py

@@ -141,7 +141,7 @@ class Bot:
         self.llm = AsyncOpenAI(base_url=LITELLM_URL, api_key=LITELLM_KEY) if LITELLM_URL else None
         self.room_models: dict[str, str] = {}  # room_id -> model name
         self.auto_rename_rooms: set[str] = set()  # rooms with auto-rename enabled
-        self.renamed_rooms: set[str] = set()  # rooms already renamed this session
+        self.renamed_rooms: dict[str, float] = {}  # room_id -> timestamp of last rename
         self._loaded_rooms: set[str] = set()  # rooms where we've loaded state
         self._sync_token_received = False
         self._verifications: dict[str, dict] = {}  # txn_id -> verification state
@@ -483,12 +483,14 @@ class Bot:
             )
             reply = resp.choices[0].message.content
             await self._send_text(room.room_id, reply)
-            # Auto-rename room after first AI response
+            # Auto-rename room after first AI response or after a conversation gap
             # In DMs: always auto-rename. In groups: only if explicitly enabled.
             is_dm = room.member_count == 2
+            last_rename = self.renamed_rooms.get(room.room_id, 0)
+            gap_seconds = time.time() - last_rename if last_rename else float("inf")
             should_rename = (
-                room.room_id not in self.renamed_rooms
-                and (is_dm or room.room_id in self.auto_rename_rooms)
+                (is_dm or room.room_id in self.auto_rename_rooms)
+                and gap_seconds > 300  # Re-rename after 5min gap (new topic)
             )
             if should_rename:
                 await self._auto_rename_room(room, user_message, reply)
@@ -535,11 +537,7 @@ class Bot:
 
     async def _auto_rename_room(self, room, user_message: str, ai_reply: str):
         """Generate a short topic title and set it as the room name (Open WebUI style)."""
-        # Skip if room already has a meaningful name (not default)
-        current_name = getattr(room, "name", "") or ""
-        if current_name and current_name.lower() not in ("", "ai", "empty room", "new chat"):
-            self.renamed_rooms.add(room.room_id)
-            return
+        # Skip rename check — always generate fresh title based on current conversation
 
         try:
             resp = await self.llm.chat.completions.create(
@@ -564,7 +562,7 @@ class Bot:
                 room.room_id, "m.room.name",
                 {"name": title}, state_key="",
             )
-            self.renamed_rooms.add(room.room_id)
+            self.renamed_rooms[room.room_id] = time.time()
             logger.info("Auto-renamed room %s to: %s", room.room_id, title)
         except Exception:
             logger.debug("Auto-rename failed", exc_info=True)