Fix: exit gracefully when auth needed in daemon mode

If WhatsApp authentication is required but the process is running
non-interactively (as a launchd daemon), exit with an error instead
of showing a QR code that nobody will see.

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

src/index.ts

@@ -356,9 +356,16 @@ async function connectWhatsApp(): Promise<void> {
     const { connection, lastDisconnect, qr } = update;
 
     if (qr) {
+      // Only show QR if running interactively (not as a background daemon)
+      if (process.stdout.isTTY) {
         console.log('\nScan this QR code with WhatsApp:\n');
         qrcode.generate(qr, { small: true });
         console.log('\nWaiting for scan...\n');
+      } else {
+        logger.error('WhatsApp authentication required but running non-interactively.');
+        logger.error('Run "npm run dev" manually to scan the QR code, then restart the service.');
+        process.exit(1);
+      }
     }
 
     if (connection === 'close') {