fix: await killPort before starting each Next.js server

- Ensure port cleanup is awaited for proper async execution
- Fixes race condition where port might not be fully released

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: ScriptedAlchemy

federated-css/scripts/start-all.cjs

@@ -120,7 +120,7 @@ async function main() {
   console.log('[federated-css] starting Next consumers (sequential dev servers)...');
   for (const { dir, port } of nextConsumers) {
     // Extra cleanup for each Next.js port in case previous one didn't clean up properly
-    killPort(port);
+    await killPort(port);
     await new Promise(resolve => setTimeout(resolve, 500)); // Small delay to ensure port is released
     const cwd = path.join('consumers-nextjs', dir);
     const p = run('pnpm', ['-C', cwd, 'run', 'start']);