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-layout.css

@@ -276,4 +276,21 @@ swp-day-column {
 swp-events-layer {
   position: absolute;
   inset: 0;
+  z-index: 10;
+}
+
+/* Unavailable time zones (outside working hours) */
+swp-unavailable-layer {
+  position: absolute;
+  inset: 0;
+  z-index: 5;
+  pointer-events: none;
+}
+
+swp-unavailable-zone {
+  position: absolute;
+  left: 0;
+  right: 0;
+  background: var(--color-unavailable, rgba(0, 0, 0, 0.05));
+  pointer-events: none;
 }