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

wwwroot/css/v2/calendar-v2-base.css

@@ -25,6 +25,7 @@
   /* Colors - Grid */
   --color-hour-line: rgba(0, 0, 0, 0.2);
   --color-grid-line-light: rgba(0, 0, 0, 0.05);
+  --color-unavailable: rgba(0, 0, 0, 0.02);
 
   /* Named color palette for events (fra V1) */
   --b-color-red: #e53935;