feat: implement QR code scan login system with admin control

- Add scan login service with Redis-based token management
- Add scan login API routes for token generation and validation
- Add QRCodeLogin component for PC-side QR code display
- Add EntryQRCode component for mass login scenarios
- Add ScanLoginView for mobile-side login form
- Add localStorage persistence for user identity
- Add logout functionality to mobile client
- Add auto-redirect for logged-in users
- Add admin console control for QR code display on big screen
- Add socket event forwarding from admin to screen display

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

packages/server/src/index.ts

@@ -34,10 +34,11 @@ async function main(): Promise<void> {
     logger.info('Initializing Socket.io...');
     await initializeSocket(httpServer);
 
-    // Start server
-    httpServer.listen(config.port, () => {
+    // Start server - listen on all interfaces for LAN access
+    httpServer.listen(config.port, '0.0.0.0', () => {
       logger.info({ port: config.port, env: config.nodeEnv }, 'Server started');
       logger.info(`Health check: http://localhost:${config.port}/health`);
+      logger.info(`LAN access: http://192.168.1.5:${config.port}`);
     });
 
     // Graceful shutdown