feat(notifications): add admin notification acknowledgement on booking state changes

- Add AcknowledgePendingBookingNotification helper for acknowledging notifications
- ConfirmBookingHandler: acknowledge pending notification when booking confirmed
- Cancel handlers: acknowledge pending notification and only create cancelled_booking notification if booking was not in pending status
- Add user_notification_preferences table with email, sms, push enabled flags
- Update cancellation logic to check original status before creating notifications

init-scripts/init-script.sql

@@ -351,6 +351,21 @@ CREATE TABLE admin_notifications (
     created_at TIMESTAMPTZ DEFAULT NOW()
 );
 
+-- User notification preferences for future user notification system
+CREATE TABLE user_notification_preferences (
+    id SERIAL PRIMARY KEY,
+    user_id CHAR(12) REFERENCES users(id) ON DELETE CASCADE,
+    notification_type VARCHAR(50) NOT NULL,
+    email_enabled BOOLEAN DEFAULT true,
+    sms_enabled BOOLEAN DEFAULT true,
+    push_enabled BOOLEAN DEFAULT true,
+    created_at TIMESTAMPTZ DEFAULT NOW(),
+    updated_at TIMESTAMPTZ DEFAULT NOW(),
+    UNIQUE(user_id, notification_type)
+);
+
+CREATE INDEX idx_user_notification_preferences_user_id ON user_notification_preferences(user_id);
+
 CREATE INDEX idx_payments_booking_id_status ON payments(booking_id, status);
 CREATE INDEX idx_bookings_start_time_status ON bookings(start_time, status);
 CREATE INDEX idx_users_created_at ON users(created_at);