feat(ui): adopt Tailwind v4 design system and archive change

- Add tailwindcss v4 + @tailwindcss/vite to mall, shop-admin, admin
- Add @vmall/shared/theme.css tokens with html[data-accent] presets
- Add @vmall/ui kit (VBtn/VBadge/VField/VInput/VCard/VPanel/VTable/VPage,
  VAccentSwatch, useAccent) as a Nuxt module
- Convert all three apps to kit + utilities; delete ui.css/mall.css and
  every <style scoped>; consoles get accent presets, mall locked to red
- Fix VCard boolean prop default (padding) and PDP/store stale
  useAsyncData keys on param navigation
- Archive adopt-tailwind-design-system; new frontend-ui capability spec

apps/mall/components/PriceText.vue

@@ -27,6 +27,6 @@ watch(
 </script>
 
 <template>
-  <span v-if="failed" class="muted">{{ $t("mall.notAvailable") }}</span>
+  <span v-if="failed" class="text-muted">{{ $t("mall.notAvailable") }}</span>
   <span v-else>{{ display || $t("common.loading") }}</span>
 </template>