feat: complete UI/UX overhaul - dashboard unification, calendar UX, mobile optimization

- Dashboard redesign as command center with filters, quick actions, inline approve/reject
- Reusable components: BookingRow, BookingFilters, ActionMenu, BookingPreviewModal, BookingEditModal
- Calendar: drag & drop reschedule, eventClick preview modal, grid/list toggle
- Mobile: segmented control bookings/calendar toggle, compact pills, responsive layout
- Collapsible filters with active count badge
- Smart menu positioning with Teleport
- Calendar/list bidirectional data sync
- Navigation: unified History page, removed AdminPending
- Google Calendar OAuth integration
- Dark mode contrast improvements, breadcrumb navigation
- useLocalStorage composable for state persistence

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/App.vue

@@ -117,7 +117,7 @@ const handleNotificationClick = async (notification: Notification) => {
 
   if (notification.booking_id) {
     closeNotifications()
-    router.push('/my-bookings')
+    router.push('/history')
   }
 }