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/ui/Breadcrumb.vue

@@ -3,33 +3,11 @@ defineProps<{ items: { label: string; to?: string }[] }>();
 </script>
 
 <template>
-  <nav class="crumbs w1200" aria-label="breadcrumb">
+  <nav aria-label="breadcrumb" class="mx-auto my-5 max-w-mall px-4 text-[13px] text-muted">
     <template v-for="(item, i) in items" :key="i">
-      <NuxtLink v-if="item.to" :to="item.to">{{ item.label }}</NuxtLink>
-      <span v-else class="here">{{ item.label }}</span>
-      <span v-if="i < items.length - 1" class="sep">/</span>
+      <NuxtLink v-if="item.to" :to="item.to" class="no-underline transition-colors hover:text-primary">{{ item.label }}</NuxtLink>
+      <span v-else class="text-text">{{ item.label }}</span>
+      <span v-if="i < items.length - 1" class="mx-2 text-muted/60">/</span>
     </template>
   </nav>
 </template>
-
-<style scoped>
-.crumbs {
-  margin: 20px auto;
-  font-size: 13px;
-  color: var(--mall-muted);
-}
-a {
-  color: var(--mall-muted);
-  text-decoration: none;
-}
-a:hover {
-  color: var(--mall-red);
-}
-.sep {
-  margin: 0 8px;
-  color: var(--mall-faint);
-}
-.here {
-  color: var(--mall-ink);
-}
-</style>