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/shop-admin/package.json

@@ -14,6 +14,11 @@
     "nuxt": "^3.15.4",
     "pinia": "^2.3.1",
     "vue": "^3.5.13",
-    "vue-router": "^4.5.0"
+    "vue-router": "^4.5.0",
+    "@vmall/ui": "workspace:*"
+  },
+  "devDependencies": {
+    "@tailwindcss/vite": "^4.1.13",
+    "tailwindcss": "^4.1.13"
   }
 }