Add dashboard and navigation translations with date-fns locale support

- Add translations for all dashboard widgets (de, es, fr)
- Add navigation menu translations for all languages
- Create useDateFnsLocale hook for localized date formatting
- Add translate="no" to prevent browser auto-translation
- Update dashboard components to use translation keys

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

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

frontend/src/i18n/locales/en.json

@@ -132,6 +132,12 @@
     "expandSidebar": "Expand sidebar",
     "collapseSidebar": "Collapse sidebar",
     "smoothSchedule": "Smooth Schedule",
+    "gallery": "Media Gallery",
+    "siteBuilder": "Site Builder",
+    "mySchedule": "My Schedule",
+    "myAvailability": "My Availability",
+    "timeBlocks": "Time Blocks",
+    "helpDocs": "Help & Docs",
     "sections": {
       "manage": "Manage",
       "communicate": "Communicate",
@@ -1322,7 +1328,57 @@
     "week": "Week",
     "month": "Month",
     "weekLabel": "Week:",
-    "monthLabel": "Month:"
+    "monthLabel": "Month:",
+    "done": "Done",
+    "editLayout": "Edit Layout",
+    "widgets": "Widgets",
+    "editModeHint": "Drag widgets to reposition them. Drag the corner to resize. Hover over a widget and click the X to remove it.",
+    "configureWidgets": "Configure Dashboard Widgets",
+    "configureWidgetsDescription": "Select which widgets to show on your dashboard. You can drag widgets to reposition them.",
+    "resetToDefault": "Reset to Default",
+    "openTickets": "Open Tickets",
+    "urgent": "urgent",
+    "open": "open",
+    "overdue": "Overdue",
+    "viewAllTickets": "View all {{count}} tickets",
+    "newBooking": "New Booking",
+    "customerBookedAppointment": "{{customerName}} booked an appointment",
+    "cancellation": "Cancellation",
+    "customerCancelledAppointment": "{{customerName}} cancelled their appointment",
+    "completed": "Completed",
+    "customerAppointmentCompleted": "{{customerName}}'s appointment completed",
+    "newCustomer": "New Customer",
+    "customerSignedUp": "{{customerName}} signed up",
+    "capacityThisWeek": "Capacity This Week",
+    "customersThisMonth": "Customers This Month",
+    "new": "New",
+    "returning": "Returning",
+    "widgetTitles": {
+      "appointmentsMetric": "Total Appointments",
+      "customersMetric": "Active Customers",
+      "servicesMetric": "Services",
+      "resourcesMetric": "Resources",
+      "revenueChart": "Revenue",
+      "appointmentsChart": "Appointments Trend",
+      "openTickets": "Open Tickets",
+      "recentActivity": "Recent Activity",
+      "capacityUtilization": "Capacity Utilization",
+      "noShowRate": "No-Show Rate",
+      "customerBreakdown": "New vs Returning"
+    },
+    "widgetDescriptions": {
+      "appointmentsMetric": "Shows appointment count with weekly and monthly growth",
+      "customersMetric": "Shows customer count with weekly and monthly growth",
+      "servicesMetric": "Shows number of services offered",
+      "resourcesMetric": "Shows number of resources available",
+      "revenueChart": "Weekly revenue bar chart",
+      "appointmentsChart": "Weekly appointments line chart",
+      "openTickets": "Shows open support tickets requiring attention",
+      "recentActivity": "Timeline of recent business events",
+      "capacityUtilization": "Shows how booked your resources are this week",
+      "noShowRate": "Percentage of appointments marked as no-show",
+      "customerBreakdown": "Customer breakdown this month"
+    }
   },
   "scheduler": {
     "title": "Scheduler",