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/pubspec.lock

@@ -1079,6 +1079,13 @@ packages:
       relative: true
     source: path
     version: "0.0.1"
+  staff_availability:
+    dependency: transitive
+    description:
+      path: "packages/features/staff/availability"
+      relative: true
+    source: path
+    version: "0.0.1"
   staff_bank_account:
     dependency: transitive
     description: