Adds dynamic header hiding for date groupings

Introduces hideHeader option for date grouping configurations
Enables suppressing date headers in specific views like day view
Improves calendar view flexibility by conditionally rendering headers

src/v2/core/CalendarOrchestrator.ts

@@ -43,7 +43,7 @@ export class CalendarOrchestrator {
     // Resolve belongsTo relations (e.g., team.resourceIds)
     const { parentChildMap, childType } = await this.resolveBelongsTo(viewConfig.groupings, filter);
 
-    const context: IRenderContext = { headerContainer, columnContainer, filter, parentChildMap, childType };
+    const context: IRenderContext = { headerContainer, columnContainer, filter, groupings: viewConfig.groupings, parentChildMap, childType };
 
     // Clear
     headerContainer.innerHTML = '';

src/v2/core/IGroupingRenderer.ts

@@ -1,7 +1,10 @@
+import { GroupingConfig } from './ViewConfig';
+
 export interface IRenderContext {
   headerContainer: HTMLElement;
   columnContainer: HTMLElement;
   filter: Record<string, string[]>;  // { team: ['alpha'], resource: ['alice', 'bob'], date: [...] }
+  groupings?: GroupingConfig[];      // Full grouping configs (for hideHeader etc.)
   parentChildMap?: Record<string, string[]>;  // { team1: ['EMP001', 'EMP002'], team2: ['EMP003', 'EMP004'] }
   childType?: string;  // The type of the child grouping (e.g., 'resource' when team has belongsTo)
 }

src/v2/core/ViewConfig.ts

@@ -15,4 +15,5 @@ export interface GroupingConfig {
   idProperty?: string;      // Property-navn på event (f.eks. 'resourceId') - kun for event matching
   derivedFrom?: string;     // Hvis feltet udledes fra anden property (f.eks. 'date' fra 'start')
   belongsTo?: string;       // Parent-child relation (f.eks. 'team.resourceIds')
+  hideHeader?: boolean;     // Skjul header-rækken for denne grouping (f.eks. dato i day-view)
 }