Add mobile accessibility and UI/UX improvements

- Add mobile card view for packages (replaces table on small screens)
- Implement design tokens system for consistent styling
- Add dark/light theme toggle with system preference support
- Create reusable StatusBadge and EmptyState components
- Add accessible form labels to package filters
- Add compact mobile stats display in navigation
- Add safe area insets for notched devices
- Add reduced motion support for accessibility
- Improve touch targets for WCAG compliance
- Add unit tests for composables
- Update Vuetify configuration and styling

frontend/components.d.ts

@@ -11,12 +11,15 @@ declare module 'vue' {
     BuildServerStats: typeof import('./src/components/BuildServerStats.vue')['default']
     BuildStats: typeof import('./src/components/MainNav/BuildStats.vue')['default']
     CurrentlyBuilding: typeof import('./src/components/CurrentlyBuilding.vue')['default']
+    EmptyState: typeof import('./src/components/common/EmptyState.vue')['default']
     MainNav: typeof import('./src/components/MainNav.vue')['default']
+    PackageCard: typeof import('./src/components/Packages/PackageCard.vue')['default']
     PackageFilters: typeof import('./src/components/Packages/PackageFilters.vue')['default']
     Packages: typeof import('./src/components/Packages.vue')['default']
     PackageTable: typeof import('./src/components/Packages/PackageTable.vue')['default']
     QueuedPackagesList: typeof import('./src/components/CurrentlyBuilding/QueuedPackagesList.vue')['default']
     StatItem: typeof import('./src/components/MainNav/BuildStats/StatItem.vue')['default']
     StatsListSection: typeof import('./src/components/MainNav/BuildStats/StatsListSection.vue')['default']
+    StatusBadge: typeof import('./src/components/common/StatusBadge.vue')['default']
   }
 }