Implement browser notification system for calendar event alarms

- Add comprehensive alarm scheduling and notification system
- Support for VAlarm data structures from calendar events
- Browser notification API integration with permission handling
- localStorage persistence for alarms across sessions
- Background service worker for alarm checking when app inactive
- Real-time alarm detection with 30-second intervals
- Debug logging for troubleshooting notification issues
- Automatic permission requests when events with alarms are created
- Support for Display action alarms with Duration and DateTime triggers
- Clean alarm management (create, update, remove, expire)

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

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

frontend/index.html

@@ -8,6 +8,7 @@
     <link data-trunk rel="css" href="styles.css">
     <link data-trunk rel="css" href="print-preview.css">
     <link data-trunk rel="copy-file" href="styles/google.css">
+    <link data-trunk rel="copy-file" href="service-worker.js">
     <link data-trunk rel="icon" href="favicon.ico">
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css" integrity="sha512-DTOQO9RWCH3ppGqcWaEA1BIZOC6xxalwEsw9c2QQeAIftl+Vegovlnee1c9QX4TctnWMn13TZye+giMm8e2LwA==" crossorigin="anonymous" referrerpolicy="no-referrer" />
 </head>
@@ -17,6 +18,19 @@
         window.addEventListener('TrunkApplicationStarted', () => {
             console.log("Trunk application started successfully!");
         });
+
+        // Register service worker for alarm background processing
+        if ('serviceWorker' in navigator) {
+            window.addEventListener('load', () => {
+                navigator.serviceWorker.register('/service-worker.js')
+                    .then((registration) => {
+                        console.log('SW registered: ', registration);
+                    })
+                    .catch((registrationError) => {
+                        console.log('SW registration failed: ', registrationError);
+                    });
+            });
+        }
     </script>
 </body>
 </html>