feat: enhance checkout process with purchase editing and status handling

- Implemented purchase editing functionality in CheckoutPageComponent, allowing users to modify items in their purchase.
- Added a new guard (checkoutPendingPurchaseGuard) to prevent navigation away from the checkout page while a purchase is in progress.
- Updated the login page to handle return URLs after authentication.
- Enhanced product detail page to support direct purchases with a new buyNow method.
- Introduced new UI elements and logic to handle purchase status, including expired and rejected states in PurchaseStatusPageComponent.
- Improved cart component to allow editing of item quantities with a toggle button.
- Added quantity selector enhancements to disable controls when necessary.
- Updated tests to cover new functionalities and ensure proper behavior of components.

src/app/shared/components/cart-item/cart-item.component.ts

@@ -23,6 +23,9 @@ export class CartItemComponent {
   readonly discountPercentage = input<number | null>(null);
   readonly attributes = input<CartItemAttribute[]>([]);
   readonly quantity = input<number>(1);
+  readonly readonly = input<boolean>(false);
+  readonly quantityDisabled = input<boolean>(false);
+  readonly showRemove = input<boolean>(true);
 
   readonly quantityChange = output<number>();
   readonly remove = output<void>();
@@ -30,6 +33,7 @@ export class CartItemComponent {
   readonly decrease = output<void>();
 
   protected onQuantityChange(newQuantity: number): void {
+    if (this.quantityDisabled()) return;
     this.quantityChange.emit(newQuantity);
   }