Fix worker ID mapping - use database ID for command routing

Problem:
- Workers generate random UUID on startup (runtime ID)
- Database stores workers with persistent IDs (database ID)
- UI sends commands using database ID
- Server couldn't find worker connection (stored by runtime ID)
- Result: 400 Bad Request "Worker not connected"

Solution:
- When worker connects, look up database ID by worker name
- Store WebSocket connection in Map using BOTH IDs:
  * Runtime ID (from worker_connect message)
  * Database ID (from database lookup by name)
- Commands from UI use database ID → finds correct WebSocket
- Cleanup both IDs when worker disconnects

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

server.js

@@ -179,21 +179,40 @@ wss.on('connection', (ws) => {
         const { worker_id, worker_name } = message;
         console.log(`Worker connected: ${worker_name} (${worker_id})`);
 
-        // Store worker WebSocket connection
-        workers.set(worker_id, ws);
+        // Find the database worker ID by name
+        const [dbWorkers] = await pool.query(
+          'SELECT id FROM workers WHERE name = ?',
+          [worker_name]
+        );
+
+        if (dbWorkers.length > 0) {
+          const dbWorkerId = dbWorkers[0].id;
+
+          // Store worker WebSocket connection using BOTH IDs
+          workers.set(worker_id, ws);        // Runtime ID
+          workers.set(dbWorkerId, ws);       // Database ID
+
+          // Store mapping for cleanup
+          ws.workerId = worker_id;
+          ws.dbWorkerId = dbWorkerId;
+
+          console.log(`Mapped worker: runtime_id=${worker_id}, db_id=${dbWorkerId}, name=${worker_name}`);
 
           // Update worker status to online
           await pool.query(
             `UPDATE workers SET status='online', last_heartbeat=NOW() WHERE id=?`,
-          [worker_id]
+            [dbWorkerId]
           );
 
-        // Broadcast worker status update
+          // Broadcast worker status update with database ID
           broadcast({
             type: 'worker_update',
-          worker_id: worker_id,
+            worker_id: dbWorkerId,
             status: 'online'
           });
+        } else {
+          console.log(`Worker ${worker_name} not found in database, will be created on heartbeat`);
+        }
       }
 
       if (message.type === 'pong') {
@@ -212,13 +231,14 @@ wss.on('connection', (ws) => {
 
   ws.on('close', () => {
     clients.delete(ws);
-    // Remove worker from workers map when disconnected
-    for (const [workerId, workerWs] of workers.entries()) {
-      if (workerWs === ws) {
-        workers.delete(workerId);
-        console.log(`Worker ${workerId} disconnected`);
-        break;
+    // Remove worker from workers map when disconnected (both runtime and db IDs)
+    if (ws.workerId) {
+      workers.delete(ws.workerId);
+      console.log(`Worker ${ws.workerId} (runtime ID) disconnected`);
     }
+    if (ws.dbWorkerId) {
+      workers.delete(ws.dbWorkerId);
+      console.log(`Worker ${ws.dbWorkerId} (database ID) disconnected`);
     }
   });
 });