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/vitest.config.ts

@@ -0,0 +1,22 @@
+import { defineConfig } from 'vitest/config'
+import vue from '@vitejs/plugin-vue'
+import { fileURLToPath } from 'node:url'
+
+export default defineConfig({
+  plugins: [vue()],
+  test: {
+    environment: 'happy-dom',
+    globals: true,
+    include: ['src/**/*.{test,spec}.{js,ts,vue}'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'html'],
+      exclude: ['node_modules', 'src/generated', 'dist'],
+    },
+  },
+  resolve: {
+    alias: {
+      '@': fileURLToPath(new URL('./src', import.meta.url)),
+    },
+  },
+})