fix(ui): make notification countdown update reactively

The "Time Until" field in NotificationsView was not updating when
refresh was clicked or over time because the computed property used
Date.now() directly, which is evaluated once and doesn't trigger
reactive updates.

Changes:
- Add reactive currentTime property that updates every second
- Set up interval in mounted() to keep countdown live
- Clean up interval in beforeUnmount() to prevent memory leaks
- Update timeUntilNext computed to use reactive currentTime
- Update refreshNotifications() to immediately refresh currentTime

The countdown now updates automatically every second and immediately
when the refresh button is clicked, without requiring navigation away
and back to the view.

test-apps/daily-notification-test/src/views/NotificationsView.vue

@@ -139,9 +139,22 @@ class NotificationsView extends Vue {
   errorMessage = ''
   notificationStatus: NotificationStatus | null = null
   rolloverInfo: RolloverInfo | null = null
+  currentTime = Date.now()
+  private timeUpdateInterval: number | null = null
 
   async mounted() {
     await this.refreshNotifications()
+    // Update current time every second to keep countdown reactive
+    this.timeUpdateInterval = window.setInterval(() => {
+      this.currentTime = Date.now()
+    }, 1000)
+  }
+
+  beforeUnmount() {
+    if (this.timeUpdateInterval !== null) {
+      clearInterval(this.timeUpdateInterval)
+      this.timeUpdateInterval = null
+    }
   }
 
   goBack() {
@@ -151,6 +164,8 @@ class NotificationsView extends Vue {
   async refreshNotifications() {
     this.isLoading = true
     this.errorMessage = ''
+    // Update current time immediately to refresh countdown
+    this.currentTime = Date.now()
     
     try {
       const platform = Capacitor.getPlatform()
@@ -231,8 +246,7 @@ class NotificationsView extends Vue {
 
   get timeUntilNext(): string | null {
     if (!this.nextNotificationTime) return null
-    const now = Date.now()
-    const diff = this.nextNotificationTime - now
+    const diff = this.nextNotificationTime - this.currentTime
     
     if (diff < 0) return 'Past due'