feat: Implement full CRUD API for product categories and products, including recursive product counts for categories.

app/Models/ProductCategories.php

@@ -29,7 +29,9 @@ class ProductCategories extends Model
 
     public function children()
     {
-        return $this->hasMany(ProductCategories::class, 'parent_id')->with('children');
+        return $this->hasMany(ProductCategories::class, 'parent_id')
+            ->withCount('products')
+            ->with('children');
     }
 
     public function products()
@@ -37,6 +39,23 @@ class ProductCategories extends Model
         return $this->hasMany(Product::class, 'product_categories_id');
     }
 
+    /**
+     * Recursively count products in this category and all descendants.
+     * Requires `withCount('products')` and `with('children')` to be loaded.
+     */
+    public function getRecursiveProductsCountAttribute(): int
+    {
+        $count = (int) ($this->products_count ?? 0);
+
+        if ($this->relationLoaded('children')) {
+            foreach ($this->children as $child) {
+                $count += $child->recursive_products_count;
+            }
+        }
+
+        return $count;
+    }
+
     public function getTypeLabelAttribute(): ?string
     {
         if (!$this->type) {