feat(admin): separate platform CRUD from CMS, add entity selector macro

- Move platforms menu from CMS to Platform Admin section with create/edit
- Add platform create page, API endpoint, and service method
- Remove CMS-specific content from platform list and detail pages
- Create shared entity_selector + entity_selected_badge Jinja macros
- Create entity-selector.js generalizing store-selector.js for any entity
- Add Tom Select merchant filter to stores page with localStorage persistence
- Migrate store-products page to use shared macros (remove 53 lines of duped CSS)
- Fix broken icons: puzzle→puzzle-piece, building-storefront→store, language→translate, server→cube

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/catalog/templates/catalog/admin/store-products.html

@@ -5,62 +5,18 @@
 {% from 'shared/macros/alerts.html' import loading_state, error_state %}
 {% from 'shared/macros/tables.html' import table_wrapper %}
 {% from 'shared/macros/modals.html' import modal_simple %}
+{% from 'shared/macros/inputs.html' import entity_selector, entity_selected_badge %}
 
 {% block title %}Store Products{% endblock %}
 
 {% block alpine_data %}adminStoreProducts(){% endblock %}
 
-{% block extra_head %}
-<!-- Tom Select CSS with local fallback -->
-<link
-    rel="stylesheet"
-    href="https://cdn.jsdelivr.net/npm/tom-select@2.4.1/dist/css/tom-select.default.min.css"
-    onerror="this.onerror=null; this.href='{{ url_for('static', path='shared/css/store/tom-select.default.min.css') }}';"
-/>
-<style>
-    /* Tom Select dark mode overrides */
-    .dark .ts-wrapper .ts-control {
-        background-color: rgb(55 65 81);
-        border-color: rgb(75 85 99);
-        color: rgb(209 213 219);
-    }
-    .dark .ts-wrapper .ts-control input {
-        color: rgb(209 213 219);
-    }
-    .dark .ts-wrapper .ts-control input::placeholder {
-        color: rgb(156 163 175);
-    }
-    .dark .ts-dropdown {
-        background-color: rgb(55 65 81);
-        border-color: rgb(75 85 99);
-        color: rgb(209 213 219);
-    }
-    .dark .ts-dropdown .option {
-        color: rgb(209 213 219);
-    }
-    .dark .ts-dropdown .option.active {
-        background-color: rgb(147 51 234);
-        color: white;
-    }
-    .dark .ts-dropdown .option:hover {
-        background-color: rgb(75 85 99);
-    }
-    .dark .ts-wrapper.focus .ts-control {
-        border-color: rgb(147 51 234);
-        box-shadow: 0 0 0 1px rgb(147 51 234);
-    }
-</style>
-{% endblock %}
-
 {% block content %}
 <!-- Page Header with Store Selector -->
 {% call page_header_flex(title='Store Products', subtitle='Browse store-specific product catalogs with override capability') %}
     <div class="flex items-center gap-4">
         <!-- Store Autocomplete (Tom Select) -->
-        <div class="w-80">
-            <select id="store-select" x-ref="storeSelect" placeholder="Filter by store...">
-            </select>
-        </div>
+        {{ entity_selector(ref_name='storeSelect', id='store-select', placeholder='Filter by store...') }}
         {{ refresh_button(loading_var='loading', onclick='refresh()', variant='secondary') }}
         <a
             href="/admin/store-products/create"
@@ -73,23 +29,7 @@
 {% endcall %}
 
 <!-- Selected Store Info -->
-<div x-show="selectedStore" x-transition class="mb-6 p-3 bg-purple-50 dark:bg-purple-900/20 rounded-lg border border-purple-200 dark:border-purple-800">
-    <div class="flex items-center justify-between">
-        <div class="flex items-center gap-3">
-            <div class="w-8 h-8 rounded-full bg-purple-100 dark:bg-purple-900 flex items-center justify-center">
-                <span class="text-sm font-semibold text-purple-600 dark:text-purple-300" x-text="selectedStore?.name?.charAt(0).toUpperCase()"></span>
-            </div>
-            <div>
-                <span class="font-medium text-purple-800 dark:text-purple-200" x-text="selectedStore?.name"></span>
-                <span class="ml-2 text-xs text-purple-600 dark:text-purple-400 font-mono" x-text="selectedStore?.store_code"></span>
-            </div>
-        </div>
-        <button @click="clearStoreFilter()" class="text-purple-600 dark:text-purple-400 hover:text-purple-800 dark:hover:text-purple-200 text-sm flex items-center gap-1">
-            <span x-html="$icon('x', 'w-4 h-4')"></span>
-            Clear filter
-        </button>
-    </div>
-</div>
+{{ entity_selected_badge(entity_var='selectedStore', clear_fn='clearStoreFilter()', code_field='store_code', color='purple') }}
 
 {{ loading_state('Loading products...') }}