feat(web): add WebSocket chat handler with message persistence

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/server/index.ts

@@ -8,6 +8,7 @@ import { promptsRouter } from './routes/prompts';
 import { pipelineRouter } from './routes/pipeline';
 import { assetsRouter } from './routes/assets';
 import { configsRouter } from './routes/configs';
+import { handleChat } from './ws/chat';
 
 const app = express();
 const server = createServer(app);
@@ -22,13 +23,7 @@ app.use('/api/pipeline', pipelineRouter);
 app.use('/api/assets', assetsRouter);
 app.use('/api/configs', configsRouter);
 
-wss.on('connection', (ws) => {
-  // Placeholder - will be replaced in Task 3.1
-  console.log('WebSocket client connected');
-  ws.on('message', (data) => {
-    console.log('received:', data.toString());
-  });
-});
+wss.on('connection', handleChat);
 
 const PORT = 3001;
 initDb();