refactor(catalog): Complete catalog refactor to simplify its data model and its querying.

source commits: refactor/catalog

app/Domains/Cart/Resources/CartResource.php

@@ -21,7 +21,8 @@ class CartResource extends JsonResource
             : collect();
 
         $subtotal = $items->reduce(
-            fn (float $carry, $item): float => $carry + ((float) ($item->buyable?->getPrice() ?? 0) * $item->cantidad),
+            fn (float $carry, $item): float => $carry
+                + ((float) ($item->selectedItem()?->getPrice() ?? 0) * $item->cantidad),
             0.0,
         );