Adds department view to calendar application

Introduces department-level grouping and rendering in the calendar view

Extends the application to support:
- Department-based resource filtering
- Dynamic department header rendering
- Mock department data infrastructure

Enables more granular organizational views

src/v2/storage/departments/DepartmentService.ts

@@ -0,0 +1,25 @@
+import { IDepartment, EntityType, IEventBus } from '../../types/CalendarTypes';
+import { DepartmentStore } from './DepartmentStore';
+import { BaseEntityService } from '../BaseEntityService';
+import { IndexedDBContext } from '../IndexedDBContext';
+
+/**
+ * DepartmentService - CRUD operations for departments in IndexedDB
+ */
+export class DepartmentService extends BaseEntityService<IDepartment> {
+  readonly storeName = DepartmentStore.STORE_NAME;
+  readonly entityType: EntityType = 'Department';
+
+  constructor(context: IndexedDBContext, eventBus: IEventBus) {
+    super(context, eventBus);
+  }
+
+  /**
+   * Get departments by IDs
+   */
+  async getByIds(ids: string[]): Promise<IDepartment[]> {
+    if (ids.length === 0) return [];
+    const results = await Promise.all(ids.map(id => this.get(id)));
+    return results.filter((d): d is IDepartment => d !== null);
+  }
+}

src/v2/storage/departments/DepartmentStore.ts

@@ -0,0 +1,13 @@
+import { IStore } from '../IStore';
+
+/**
+ * DepartmentStore - IndexedDB ObjectStore definition for departments
+ */
+export class DepartmentStore implements IStore {
+  static readonly STORE_NAME = 'departments';
+  readonly storeName = DepartmentStore.STORE_NAME;
+
+  create(db: IDBDatabase): void {
+    db.createObjectStore(DepartmentStore.STORE_NAME, { keyPath: 'id' });
+  }
+}