feat: Implement staff availability feature with BLoC architecture

- Created AvailabilityPage with UI for managing staff availability.
- Integrated BLoC for state management, including LoadAvailability and ToggleDayStatus events.
- Added quick set options for availability (All Week, Weekdays, Weekends, Clear All).
- Implemented week navigation and day selection with visual feedback.
- Developed time slot management for each day, allowing toggling of availability.
- Established StaffAvailabilityModule for dependency injection and routing.
- Updated pubspec.yaml with necessary dependencies for the feature.

apps/mobile/packages/features/staff/staff_main/pubspec.yaml

@@ -49,6 +49,8 @@ dependencies:
     path: ../payments
   staff_time_card:
     path: ../profile_sections/finances/time_card
+  staff_availability:
+    path: ../availability
 
 dev_dependencies:
   flutter_test: