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/cart.component.spec.ts

@@ -306,4 +306,105 @@ describe('CartComponent', () => {
 
     vi.useRealTimers();
   });
+
+  it('enables quantity editing only while Modificar mode is active', async () => {
+    await TestBed.configureTestingModule({
+      imports: [CartComponent],
+      providers: [
+        {
+          provide: CartService,
+          useValue: {
+            cart: signal(null).asReadonly(),
+            updateItemQuantity: vi.fn(),
+            removeItem: vi.fn(),
+          },
+        },
+        { provide: ModalService, useValue: {} },
+        {
+          provide: ToastService,
+          useValue: { success: vi.fn(), info: vi.fn(), danger: vi.fn() },
+        },
+      ],
+    }).compileComponents();
+
+    const fixture = TestBed.createComponent(CartComponent);
+    fixture.componentRef.setInput('items', [
+      {
+        cartItemId: 10,
+        imageUrl: null,
+        product: 'Producto de prueba',
+        originalPrice: null,
+        discountedPrice: 1000,
+        discountPercentage: null,
+        attributes: [],
+        quantity: 1,
+      },
+    ]);
+    fixture.componentRef.setInput('allowEditing', true);
+    const editingChange = vi.fn();
+    fixture.componentInstance.editing.subscribe(editingChange);
+    fixture.detectChanges();
+
+    const editButton = fixture.debugElement.query(By.css('.cart-edit-btn'));
+    expect(editButton.nativeElement.textContent.trim()).toBe('Modificar');
+    expect(
+      fixture.debugElement.query(By.css('app-cart-item')).componentInstance.quantityDisabled(),
+    ).toBe(true);
+
+    editButton.nativeElement.click();
+    fixture.detectChanges();
+
+    expect(editButton.nativeElement.textContent.trim()).toBe('Listo');
+    expect(
+      fixture.debugElement.query(By.css('app-cart-item')).componentInstance.quantityDisabled(),
+    ).toBe(false);
+    expect(editingChange).toHaveBeenCalledWith(true);
+
+    editButton.nativeElement.click();
+    fixture.detectChanges();
+
+    expect(editButton.nativeElement.textContent.trim()).toBe('Modificar');
+    expect(editingChange).toHaveBeenLastCalledWith(false);
+  });
+
+  it('allows editing directly when the optional Modificar toggle is disabled', async () => {
+    await TestBed.configureTestingModule({
+      imports: [CartComponent],
+      providers: [
+        {
+          provide: CartService,
+          useValue: {
+            cart: signal(null).asReadonly(),
+            updateItemQuantity: vi.fn(),
+            removeItem: vi.fn(),
+          },
+        },
+        { provide: ModalService, useValue: {} },
+        {
+          provide: ToastService,
+          useValue: { success: vi.fn(), info: vi.fn(), danger: vi.fn() },
+        },
+      ],
+    }).compileComponents();
+
+    const fixture = TestBed.createComponent(CartComponent);
+    fixture.componentRef.setInput('items', [
+      {
+        cartItemId: 10,
+        imageUrl: null,
+        product: 'Producto de prueba',
+        originalPrice: null,
+        discountedPrice: 1000,
+        discountPercentage: null,
+        attributes: [],
+        quantity: 1,
+      },
+    ]);
+    fixture.detectChanges();
+
+    expect(fixture.debugElement.query(By.css('.cart-edit-btn'))).toBeNull();
+    expect(
+      fixture.debugElement.query(By.css('app-cart-item')).componentInstance.quantityDisabled(),
+    ).toBe(false);
+  });
 });