feat(mall): classic B2B2C PC storefront with fixed mock API layer

- Mock adapter implementing @vmall/shared ApiClient (localStorage-persisted
  cart/orders/invoices), runtime switch via mockApi flag (default on)
- Fixed bilingual mock catalog: 3-level categories, 24 products w/ SKUs,
  stores, brands, banners, floors, seckill/collective/integral, comments,
  coupons, addresses, seeded orders/shipments/invoices
- B2B2C mall shell: top bar, logo/search/cart header, dark nav + category
  mega-menu, value-prop footer, back-to-top; 1200px grid, #ca151e theme
- UI primitives replacing element-plus: carousel, pagination, breadcrumb,
  qty stepper, rating stars, modal, tabs, step bar, product card
- Pages: home floors, search (filters/sort/paging), goods detail (SKU
  picker, store rail, review tabs), cart -> checkout -> pay -> success,
  auth pages, user center (dashboard/orders/addresses/favorites/coupons/
  invoices), stores, seckill, collective, integral
- i18n split into per-domain locale modules (en+zh)
- OpenSpec change mall-pc-storefront-replica archived; all specs green

apps/mall/components/ui/RatingStars.vue

@@ -0,0 +1,19 @@
+<script setup lang="ts">
+const props = withDefaults(defineProps<{ value: number; size?: number }>(), { size: 14 });
+const stars = computed(() => [1, 2, 3, 4, 5].map((i) => i <= Math.round(props.value)));
+</script>
+
+<template>
+  <span class="stars" :style="{ fontSize: `${size}px` }">
+    <span v-for="(on, i) in stars" :key="i" :class="{ on }">★</span>
+  </span>
+</template>
+
+<style scoped>
+.stars span {
+  color: #ddd;
+}
+.stars span.on {
+  color: var(--mall-red);
+}
+</style>