feat(inventory): add InventorySubject enum and integrate into catalog item management

app/Domains/Purchase/Services/Checkout/InsufficientStockMessageBuilder.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace App\Domains\Purchase\Services\Checkout;
+
+use App\Domains\Catalog\Enums\InventorySubject;
+use App\Domains\Catalog\Models\CatalogItem;
+use App\Domains\Catalog\Models\Variant;
+
+class InsufficientStockMessageBuilder
+{
+    public function build(
+        CatalogItem $catalogItem,
+        CatalogItem|Variant $selection,
+        int $availableQuantity,
+    ): string {
+        return match ($catalogItem->inventory_subject) {
+            InventorySubject::Seat => __('api.purchase.stock.seat_unavailable', [
+                'selection' => $selection->getSelectionLabel(),
+            ]),
+            InventorySubject::Ticket => __('api.purchase.stock.ticket_unavailable', [
+                'selection' => $selection->getSelectionLabel(),
+            ]),
+            InventorySubject::Product => __('api.purchase.stock.product_unavailable', [
+                'selection' => $this->productSelectionLabel($catalogItem, $selection),
+                'max' => $availableQuantity,
+            ]),
+        };
+    }
+
+    private function productSelectionLabel(
+        CatalogItem $catalogItem,
+        CatalogItem|Variant $selection,
+    ): string {
+        if ($selection instanceof CatalogItem) {
+            return $selection->getSelectionLabel();
+        }
+
+        return __('api.purchase.stock.product_selection', [
+            'product' => $catalogItem->getName(),
+            'selection' => $selection->getSelectionLabel(),
+        ]);
+    }
+}