Sprint 7: add section engine

src/app/shared/models/config/section.model.ts

@@ -1,6 +1,17 @@
 import { WidgetConfig } from './widget.model';
 
+export type SectionViewport = 'desktop' | 'tablet' | 'mobile';
+
+export type SectionLayoutStrategy = 'stack' | 'grid' | 'hero' | 'carousel' | 'split';
+
+export interface SectionVisibilityConfig {
+  desktop?: boolean;
+  tablet?: boolean;
+  mobile?: boolean;
+}
+
 export interface SectionLayoutConfig {
+  strategy?: SectionLayoutStrategy;
   columns?: number;
   gap?: string;
   align?: 'start' | 'center' | 'end' | 'stretch';
@@ -11,6 +22,7 @@ export interface SectionConfig {
   type: string;
   order: number;
   layout?: SectionLayoutConfig;
+  visibility?: SectionVisibilityConfig;
   widgets: WidgetConfig[];
   featureFlag?: string;
   visible?: boolean;