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/domain/lib/src/entities/availability/availability_slot.dart

@@ -0,0 +1,33 @@
+import 'package:equatable/equatable.dart';
+
+/// Represents a specific time slot within a day (e.g., Morning, Afternoon, Evening).
+class AvailabilitySlot extends Equatable {
+  final String id;
+  final String label;
+  final String timeRange;
+  final bool isAvailable;
+
+  const AvailabilitySlot({
+    required this.id,
+    required this.label,
+    required this.timeRange,
+    this.isAvailable = true,
+  });
+
+  AvailabilitySlot copyWith({
+    String? id,
+    String? label,
+    String? timeRange,
+    bool? isAvailable,
+  }) {
+    return AvailabilitySlot(
+      id: id ?? this.id,
+      label: label ?? this.label,
+      timeRange: timeRange ?? this.timeRange,
+      isAvailable: isAvailable ?? this.isAvailable,
+    );
+  }
+
+  @override
+  List<Object?> get props => [id, label, timeRange, isAvailable];
+}

apps/mobile/packages/domain/lib/src/entities/availability/day_availability.dart

@@ -0,0 +1,31 @@
+import 'package:equatable/equatable.dart';
+
+import 'availability_slot.dart';
+
+/// Represents availability configuration for a specific date.
+class DayAvailability extends Equatable {
+  final DateTime date;
+  final bool isAvailable;
+  final List<AvailabilitySlot> slots;
+
+  const DayAvailability({
+    required this.date,
+    this.isAvailable = false,
+    this.slots = const [],
+  });
+
+  DayAvailability copyWith({
+    DateTime? date,
+    bool? isAvailable,
+    List<AvailabilitySlot>? slots,
+  }) {
+    return DayAvailability(
+      date: date ?? this.date,
+      isAvailable: isAvailable ?? this.isAvailable,
+      slots: slots ?? this.slots,
+    );
+  }
+
+  @override
+  List<Object?> get props => [date, isAvailable, slots];
+}