fix: use room_messages API for /messages endpoint (nio rooms have no timeline attr)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bot.py

@@ -4118,18 +4118,21 @@ class Bot:
             room = self.client.rooms.get(room_id)
             if not room:
                 return web.json_response({'error': 'room not found (bot not joined?)'}, status=404)
+            # Use room_messages API to fetch and decrypt
+            resp = await self.client.room_messages(room_id, room.prev_batch or '', limit=limit)
             messages = []
-            for event in room.timeline[-limit:]:
-                msg = {
-                    'sender': event.sender,
-                    'timestamp': getattr(event, 'server_timestamp', 0),
-                    'type': type(event).__name__,
-                }
-                if hasattr(event, 'body'):
-                    msg['body'] = event.body
-                elif hasattr(event, 'source'):
-                    msg['body'] = event.source.get('content', {}).get('body', '[encrypted/unknown]')
-                messages.append(msg)
+            if hasattr(resp, 'chunk'):
+                for event in reversed(resp.chunk):
+                    msg = {
+                        'sender': event.sender,
+                        'timestamp': getattr(event, 'server_timestamp', 0),
+                        'type': type(event).__name__,
+                    }
+                    if hasattr(event, 'body'):
+                        msg['body'] = event.body
+                    elif hasattr(event, 'source'):
+                        msg['body'] = event.source.get('content', {}).get('body', '[encrypted/unknown]')
+                    messages.append(msg)
             return web.json_response({'messages': messages})
         except Exception as e:
             logger.error("Messages error: %s", e)