feat: implement public booking cancellation feature

- Added cancelPublicBooking handler to manage booking cancellations.
- Updated public booking service to include cancellation logic.
- Created cancelPublicBooking schema for input validation.
- Modified public booking confirmation page to allow users to cancel their bookings.
- Enhanced email service to send cancellation confirmation emails.
- Made customerEmail field required in booking schemas and updated related components.
- Updated API client to support cancellation requests.
- Added migration to enforce non-nullable customer_email fields in the database.

apps/backend/src/modules/admin-booking/services/admin-booking.service.ts

@@ -199,7 +199,7 @@ function mapBookingResponse(booking: {
   endTime: string;
   customerName: string;
   customerPhone: string;
-  customerEmail: string | null;
+  customerEmail: string;
   status: 'CONFIRMED' | 'CANCELLED' | 'COMPLETED' | 'NOSHOW';
   createdAt: Date;
   updatedAt: Date;
@@ -235,7 +235,7 @@ function mapBookingResponse(booking: {
     endTime: booking.endTime,
     customerName: booking.customerName,
     customerPhone: booking.customerPhone,
-    customerEmail: booking.customerEmail ?? undefined,
+    customerEmail: booking.customerEmail,
     price: booking.price ?? 0,
     status: booking.status,
     createdAt: booking.createdAt.toISOString(),
@@ -424,7 +424,7 @@ export async function createAdminBooking(
             endTime: selectedSlot.endTime,
             customerName: input.customerName.trim(),
             customerPhone: input.customerPhone.trim(),
-            customerEmail: input.customerEmail?.trim() || null,
+            customerEmail: input.customerEmail.trim(),
             status: 'CONFIRMED',
           },
           include: {