fix(ui): replace native confirm()/alert() with shared dialogs and toasts

New app-confirm-dialog (wraps existing app-dialog + app-button) replaces
every native confirm() across media library bulk-delete, static pages
editor (delete/bulk-delete), builder save-bar (publish/reset-draft),
project-editor-page (reset-section), homepage/languages/widgets sections
(remove block/language/widget), and cart (clear-cart).

Cart's native alert() calls (delivery/terms validation, email send
success/failure) now route through the existing UserNotificationService
toast pipeline instead.

No native confirm()/alert()/prompt() remain in production UI.

src/app/shared/ui/confirm-dialog/confirm-dialog.component.html

@@ -0,0 +1,11 @@
+<app-dialog [open]="open()" [titleText]="titleText()" size="sm" (closed)="cancelled.emit()">
+  <p class="app-confirm-dialog__message">{{ message() }}</p>
+  <div class="app-confirm-dialog__actions">
+    <app-button variant="secondary" (click)="cancelled.emit()">
+      {{ cancelLabel() ?? ('common.cancel' | translate) }}
+    </app-button>
+    <app-button [variant]="destructive() ? 'danger' : 'primary'" (click)="confirmed.emit()">
+      {{ confirmLabel() ?? ('common.confirm' | translate) }}
+    </app-button>
+  </div>
+</app-dialog>

src/app/shared/ui/confirm-dialog/confirm-dialog.component.scss

@@ -0,0 +1,10 @@
+.app-confirm-dialog__message {
+  margin: 0 0 var(--space-lg, 1.5rem);
+  color: var(--text-secondary);
+}
+
+.app-confirm-dialog__actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: var(--space-sm, 0.5rem);
+}

src/app/shared/ui/confirm-dialog/confirm-dialog.component.ts

@@ -0,0 +1,24 @@
+import { ChangeDetectionStrategy, Component, input, output } from '@angular/core';
+import { DialogComponent } from '../dialog/dialog.component';
+import { ButtonComponent } from '../button/button.component';
+import { TranslatePipe } from '../../../i18n/translate.pipe';
+
+@Component({
+  selector: 'app-confirm-dialog',
+  standalone: true,
+  imports: [DialogComponent, ButtonComponent, TranslatePipe],
+  templateUrl: './confirm-dialog.component.html',
+  styleUrl: './confirm-dialog.component.scss',
+  changeDetection: ChangeDetectionStrategy.OnPush
+})
+export class ConfirmDialogComponent {
+  readonly open = input(false);
+  readonly titleText = input<string | null>(null);
+  readonly message = input<string>('');
+  readonly confirmLabel = input<string | null>(null);
+  readonly cancelLabel = input<string | null>(null);
+  readonly destructive = input(false);
+
+  readonly confirmed = output<void>();
+  readonly cancelled = output<void>();
+}