Adds resource scheduling and unavailability tracking

Introduces comprehensive schedule management for resources:
- Adds DateService with advanced time and date utilities
- Implements ResourceScheduleService for managing work hours
- Creates ScheduleRenderer to visualize unavailable time zones
- Extends resource model to support default weekly schedules

Enables granular tracking of resource availability and working hours

src/v2/core/IGridConfig.ts

@@ -0,0 +1,6 @@
+export interface IGridConfig {
+  hourHeight: number;      // pixels per hour
+  dayStartHour: number;    // e.g. 6
+  dayEndHour: number;      // e.g. 18
+  snapInterval: number;    // minutes, e.g. 15
+}