Sets up calendar package with core infrastructure

Adds core calendar package components including:
- Base services for events, resources, and settings
- Calendar app and orchestrator
- Build and bundling configuration
- IndexedDB storage setup

Prepares foundational architecture for calendar functionality

packages/calendar/src/managers/EventPersistenceManager.ts

@@ -0,0 +1,102 @@
+/**
+ * EventPersistenceManager - Persists event changes to IndexedDB
+ *
+ * Listens to drag/resize events and updates IndexedDB via EventService.
+ * This bridges the gap between UI interactions and data persistence.
+ */
+
+import { ICalendarEvent, IEventBus, IEventUpdatedPayload } from '../types/CalendarTypes';
+import { EventService } from '../storage/events/EventService';
+import { DateService } from '../core/DateService';
+import { CoreEvents } from '../constants/CoreEvents';
+import { IDragEndPayload } from '../types/DragTypes';
+import { IResizeEndPayload } from '../types/ResizeTypes';
+
+export class EventPersistenceManager {
+  constructor(
+    private eventService: EventService,
+    private eventBus: IEventBus,
+    private dateService: DateService
+  ) {
+    this.setupListeners();
+  }
+
+  private setupListeners(): void {
+    this.eventBus.on(CoreEvents.EVENT_DRAG_END, this.handleDragEnd);
+    this.eventBus.on(CoreEvents.EVENT_RESIZE_END, this.handleResizeEnd);
+  }
+
+  /**
+   * Handle drag end - update event position in IndexedDB
+   */
+  private handleDragEnd = async (e: Event): Promise<void> => {
+    const payload = (e as CustomEvent<IDragEndPayload>).detail;
+    const { swpEvent } = payload;
+
+    // Get existing event to merge with
+    const event = await this.eventService.get(swpEvent.eventId);
+    if (!event) {
+      console.warn(`EventPersistenceManager: Event ${swpEvent.eventId} not found`);
+      return;
+    }
+
+    // Parse resourceId from columnKey if present
+    const { resource } = this.dateService.parseColumnKey(swpEvent.columnKey);
+
+    // Update and save - start/end already calculated in SwpEvent
+    // Set allDay based on drop target:
+    // - header: allDay = true
+    // - grid: allDay = false (converts allDay event to timed)
+    const updatedEvent: ICalendarEvent = {
+      ...event,
+      start: swpEvent.start,
+      end: swpEvent.end,
+      resourceId: resource ?? event.resourceId,
+      allDay: payload.target === 'header',
+      syncStatus: 'pending'
+    };
+
+    await this.eventService.save(updatedEvent);
+
+    // Emit EVENT_UPDATED for EventRenderer to re-render affected columns
+    const updatePayload: IEventUpdatedPayload = {
+      eventId: updatedEvent.id,
+      sourceColumnKey: payload.sourceColumnKey,
+      targetColumnKey: swpEvent.columnKey
+    };
+    this.eventBus.emit(CoreEvents.EVENT_UPDATED, updatePayload);
+  };
+
+  /**
+   * Handle resize end - update event duration in IndexedDB
+   */
+  private handleResizeEnd = async (e: Event): Promise<void> => {
+    const payload = (e as CustomEvent<IResizeEndPayload>).detail;
+    const { swpEvent } = payload;
+
+    // Get existing event to merge with
+    const event = await this.eventService.get(swpEvent.eventId);
+    if (!event) {
+      console.warn(`EventPersistenceManager: Event ${swpEvent.eventId} not found`);
+      return;
+    }
+
+    // Update and save - end already calculated in SwpEvent
+    const updatedEvent: ICalendarEvent = {
+      ...event,
+      end: swpEvent.end,
+      syncStatus: 'pending'
+    };
+
+    await this.eventService.save(updatedEvent);
+
+    // Emit EVENT_UPDATED for EventRenderer to re-render the column
+    // Resize stays in same column, so source and target are the same
+    const updatePayload: IEventUpdatedPayload = {
+      eventId: updatedEvent.id,
+      sourceColumnKey: swpEvent.columnKey,
+      targetColumnKey: swpEvent.columnKey
+    };
+    this.eventBus.emit(CoreEvents.EVENT_UPDATED, updatePayload);
+  };
+}