refactor: simplify LoadingErrorState and enhance MarketSearchBar functionality

- Removed unnecessary imports and streamlined the LoadingErrorState component by eliminating redundant props.
- Improved keyboard handling in MarketSearchBar to support basic Escape key functionality and enhanced keyboard shortcuts.
- Updated MerchantStore and MarketPage components to utilize the revised LoadingErrorState and MarketSearchBar, ensuring consistent loading/error handling and search capabilities.
- Enhanced StallView to provide better category filtering and product search experience.

These changes improve code clarity and maintainability while enhancing user interaction across the market module.

src/modules/market/views/StallView.vue

@@ -68,8 +68,9 @@
     <CategoryFilterBar
       v-if="stallCategories.length > 0"
       :categories="stallCategories"
-      :selected-categories="selectedCategories"
+      :selected-count="selectedCategories.length"
       :filter-mode="filterMode"
+      :product-count="productCount"
       title="Categories"
       @toggle-category="toggleCategoryFilter"
       @set-filter-mode="setFilterMode"
@@ -81,7 +82,7 @@
     <div class="mb-4 sm:mb-6 flex flex-col sm:flex-row gap-2 sm:gap-4">
       <div class="flex-1">
         <MarketSearchBar
-          :data="stallProducts"
+          :data="stallProducts as Product[]"
           :options="searchOptions"
           placeholder="Search products in this stall..."
           :show-enhancements="false"
@@ -203,11 +204,20 @@ const stallProducts = computed(() => {
 
 // Get unique categories for this stall
 const stallCategories = computed(() => {
-  const categories = new Set<string>()
+  const categoryCount = new Map<string, number>()
   stallProducts.value.forEach(product => {
-    product.categories?.forEach(cat => categories.add(cat))
+    product.categories?.forEach(cat => {
+      categoryCount.set(cat, (categoryCount.get(cat) || 0) + 1)
+    })
   })
-  return Array.from(categories).sort()
+
+  return Array.from(categoryCount.entries())
+    .sort((a, b) => a[0].localeCompare(b[0]))
+    .map(([category, count]) => ({
+      category,
+      count,
+      selected: selectedCategories.value.includes(category)
+    }))
 })
 
 // Product count