feat(project-editor): adopt SectionCard in preview section

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/features/project-editor/sections/preview-section.component.html

@@ -1,5 +1,4 @@
-<section class="editor-section-card">
-  <h2>{{ 'builder.preview' | translate }}</h2>
+<app-section-card [title]="'builder.preview' | translate">
   <div class="editor-actions">
     <app-button variant="primary" (click)="preview()">{{ 'builder.livePreview' | translate }}</app-button>
     <app-button variant="secondary" (click)="refreshExport()">{{ 'builder.exportBootstrap' | translate }}</app-button>
@@ -16,4 +15,4 @@
     <span>{{ 'builder.importSource' | translate }}</span>
     <textarea rows="10" [ngModel]="importValue()" (ngModelChange)="importValue.set($event)"></textarea>
   </label>
-</section>
+</app-section-card>