fix: preserve original event type, use source field for wrapper

lib/brainstorm-server/index.js

@@ -47,7 +47,7 @@ wss.on('connection', (ws) => {
   ws.on('message', (data) => {
     // User interaction event - write to stdout for Claude
     const event = JSON.parse(data.toString());
-    console.log(JSON.stringify({ ...event, type: 'user-event' }));
+    console.log(JSON.stringify({ source: 'user-event', ...event }));
   });
 });