feat(static-pages): live device preview (desktop/tablet/mobile)

Milestone 5 of the Static Pages Module sprint.

- New StaticPagePreviewComponent: client-side, sanitized HTML preview at
  desktop/tablet(768px)/mobile(375px) widths, entirely without navigation or
  publish. Uses the same DomSanitizer.sanitize(SecurityContext.HTML, ...)
  pattern as the real storefront renderer (StaticPageComponent), so what
  authors preview here matches what will actually render live.
- Wired into static-pages-editor as a per-page collapsible "Preview" toggle,
  showing the default-locale (or first available) translation's html/title.
- i18n: staticPages.previewDesktop/Tablet/Mobile/Toggle in interface + en/ru/hy.

Gate: tsc --noEmit, npm test (57/57), arch:check, build all green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/features/content-management/components/static-page-preview/static-page-preview.component.html

@@ -0,0 +1,19 @@
+<div class="static-page-preview">
+  <div class="static-page-preview__toolbar">
+    @for (device of devices; track device.id) {
+      <app-button
+        [variant]="activeDevice() === device.id ? 'primary' : 'secondary'"
+        size="sm"
+        (click)="setDevice(device.id)"
+      >{{ device.labelKey | translate }}</app-button>
+    }
+  </div>
+  <div class="static-page-preview__viewport">
+    <div class="static-page-preview__frame" [style.width]="activeWidth()">
+      @if (title()) {
+        <h1 class="static-page-preview__title">{{ title() }}</h1>
+      }
+      <div class="static-page-preview__content" [innerHTML]="safeHtml()"></div>
+    </div>
+  </div>
+</div>

src/app/features/content-management/components/static-page-preview/static-page-preview.component.scss

@@ -0,0 +1,47 @@
+.static-page-preview {
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+}
+
+.static-page-preview__toolbar {
+  display: flex;
+  gap: 0.5rem;
+}
+
+.static-page-preview__viewport {
+  display: flex;
+  justify-content: center;
+  padding: 1rem;
+  background: var(--bg-secondary, #f5f5f5);
+  border-radius: var(--radius-md, 12px);
+  overflow-x: auto;
+}
+
+.static-page-preview__frame {
+  max-width: 100%;
+  background: var(--bg-primary, #fff);
+  border: 1px solid var(--border-color, #d3dad9);
+  border-radius: var(--radius-md, 12px);
+  padding: 1.5rem;
+  box-shadow: var(--shadow-sm, 0 2px 8px rgba(0, 0, 0, 0.1));
+}
+
+.static-page-preview__title {
+  margin: 0 0 1rem;
+  font-size: 1.5rem;
+  font-weight: 700;
+  color: var(--text-primary, #1e3c38);
+}
+
+.static-page-preview__content {
+  color: var(--text-primary, #1e3c38);
+  line-height: 1.6;
+  overflow-wrap: break-word;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .static-page-preview__frame {
+    transition: none;
+  }
+}

src/app/features/content-management/components/static-page-preview/static-page-preview.component.ts

@@ -0,0 +1,55 @@
+import { ChangeDetectionStrategy, Component, SecurityContext, computed, inject, input, signal } from '@angular/core';
+import { DomSanitizer, SafeHtml } from '@angular/platform-browser';
+import { TranslatePipe } from '../../../../i18n/translate.pipe';
+import { ButtonComponent } from '../../../../shared/ui/button/button.component';
+
+export type PreviewDevice = 'desktop' | 'tablet' | 'mobile';
+
+interface DevicePreset {
+  readonly id: PreviewDevice;
+  readonly labelKey: string;
+  readonly width: string;
+}
+
+const DEVICE_PRESETS: readonly DevicePreset[] = [
+  { id: 'desktop', labelKey: 'staticPages.previewDesktop', width: '100%' },
+  { id: 'tablet', labelKey: 'staticPages.previewTablet', width: '768px' },
+  { id: 'mobile', labelKey: 'staticPages.previewMobile', width: '375px' },
+];
+
+/**
+ * Client-side, sanitized preview of a static page's HTML at desktop/tablet/
+ * mobile widths - no navigation, no publish, no dependency on
+ * ProjectEditorPreviewService's full-app reload. Uses the same
+ * DomSanitizer.sanitize(SecurityContext.HTML, ...) pattern as the real
+ * storefront renderer (StaticPageComponent) so what you preview here is
+ * exactly what will render live.
+ */
+@Component({
+  selector: 'app-static-page-preview',
+  standalone: true,
+  imports: [TranslatePipe, ButtonComponent],
+  templateUrl: './static-page-preview.component.html',
+  styleUrl: './static-page-preview.component.scss',
+  changeDetection: ChangeDetectionStrategy.OnPush,
+})
+export class StaticPagePreviewComponent {
+  private readonly sanitizer = inject(DomSanitizer);
+
+  readonly html = input.required<string>();
+  readonly title = input<string>('');
+
+  readonly devices = DEVICE_PRESETS;
+  readonly activeDevice = signal<PreviewDevice>('desktop');
+
+  readonly activeWidth = computed(() => this.devices.find(device => device.id === this.activeDevice())?.width ?? '100%');
+
+  readonly safeHtml = computed<SafeHtml>(() => {
+    const sanitized = this.sanitizer.sanitize(SecurityContext.HTML, this.html()) ?? '';
+    return this.sanitizer.bypassSecurityTrustHtml(sanitized);
+  });
+
+  setDevice(device: PreviewDevice): void {
+    this.activeDevice.set(device);
+  }
+}

src/app/features/content-management/components/static-pages-editor.component.html

@@ -78,6 +78,7 @@
               <app-button variant="ghost" size="sm" (click)="move(page.id, -1)">&uarr;</app-button>
               <app-button variant="ghost" size="sm" (click)="move(page.id, 1)">&darr;</app-button>
               <app-button variant="secondary" size="sm" (click)="duplicatePage(page.id)">{{ 'staticPages.duplicatePage' | translate }}</app-button>
+              <app-button variant="secondary" size="sm" (click)="togglePreview(page.id)">{{ 'staticPages.previewToggle' | translate }}</app-button>
               @if (page.status === 'published') {
                 <app-button variant="secondary" size="sm" (click)="updatePage(page.id, { status: 'draft' })">{{ 'staticPages.unpublishPageAction' | translate }}</app-button>
               } @else {
@@ -87,6 +88,10 @@
             </div>
           </div>
 
+          @if (previewOpenPageId() === page.id) {
+            <app-static-page-preview [html]="previewHtml(page)" [title]="previewTitle(page)" />
+          }
+
           <div class="editor-grid three">
             <app-form-field [label]="'builder.pageId' | translate" [error]="hasEmptyTitle(page) ? ('staticPages.emptyTitle' | translate) : null">
               <app-input [ngModel]="page.id" (ngModelChange)="updatePage(page.id, { id: $event })" />

src/app/features/content-management/components/static-pages-editor.component.ts

@@ -17,6 +17,7 @@ import { SelectComponent, SelectOption } from '../../../shared/ui/select/select.
 import { ToggleComponent } from '../../../shared/ui/toggle/toggle.component';
 import { MediaPickerComponent } from '../../../shared/media/media-picker/media-picker.component';
 import { MediaAsset } from '../../../core/media/models/media-asset.model';
+import { StaticPagePreviewComponent } from './static-page-preview/static-page-preview.component';
 
 type StatusFilter = 'all' | ContentPageStatus;
 const ALL_LOCALES_FILTER = 'all';
@@ -38,6 +39,7 @@ type MediaField = 'heroImage' | 'thumbnail';
     SelectComponent,
     ToggleComponent,
     MediaPickerComponent,
+    StaticPagePreviewComponent,
   ],
   templateUrl: './static-pages-editor.component.html',
   styleUrls: ['../../project-editor/sections/section.shared.scss', './static-pages-editor.component.scss'],
@@ -119,6 +121,22 @@ export class StaticPagesEditorComponent {
     return JSON.stringify(page) !== JSON.stringify(original);
   }
 
+  readonly previewOpenPageId = signal<string | null>(null);
+
+  togglePreview(pageId: string): void {
+    this.previewOpenPageId.set(this.previewOpenPageId() === pageId ? null : pageId);
+  }
+
+  previewHtml(page: ContentPage): string {
+    const defaultLocale = this.bootstrap()?.localization.defaultLocale ?? 'en';
+    return page.translations[defaultLocale]?.html ?? Object.values(page.translations)[0]?.html ?? '';
+  }
+
+  previewTitle(page: ContentPage): string {
+    const defaultLocale = this.bootstrap()?.localization.defaultLocale ?? 'en';
+    return page.translations[defaultLocale]?.title || page.title;
+  }
+
   protected mediaPickerOpen = false;
   private mediaPickerTarget: { pageId: string; field: MediaField } | null = null;