feat(catalog): add scope to filter available variants and update related queries; enhance seeder and tests for stock validation

app/Domains/Catalog/Services/CatalogService.php

@@ -207,6 +207,7 @@ class CatalogService
 
         $paginator = CatalogItem::query()
             ->where('tenant_code', $tenant->codigo)
+            ->whereVariantsAvailable()
             ->where(function (Builder $query) use ($containsPattern): void {
                 $query
                     ->whereRaw('LOWER(nombre) LIKE ?', [$containsPattern])
@@ -257,6 +258,7 @@ class CatalogService
         return CatalogItem::query()
             ->where('tenant_code', $tenant->codigo)
             ->where('category_id', $category->id)
+            ->whereVariantsAvailable()
             ->with([
                 'attachments',
                 'inventory',