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/frontend/src/features/public-booking/public-booking-page.tsx

@@ -62,7 +62,7 @@ const bookingFormSchema = z.object({
     .trim()
     .min(6, 'Ingresá un teléfono válido.')
     .max(30, 'El teléfono no puede superar los 30 caracteres.'),
-  customerEmail: z.string().email('Ingresá un email válido.').optional().or(z.literal('')),
+  customerEmail: z.string().email('Ingresá un email válido.'),
 });
 
 type BookingFormValues = z.infer<typeof bookingFormSchema>;
@@ -1297,7 +1297,7 @@ function SelectedSlotCard(props: BookingShellProps & { compact?: boolean }) {
 
           <Field data-invalid={Boolean(errors.customerEmail)}>
             <FieldLabel htmlFor="customerEmail" className="text-white/76">
-              Email <span className="text-white/40 font-normal">(opcional)</span>
+              Email
             </FieldLabel>
             <Input
               id="customerEmail"
@@ -1445,7 +1445,7 @@ export function PublicBookingPage({ complexSlug }: PublicBookingPageProps) {
         startTime: selectedSlot.startTime,
         customerName: payload.customerName,
         customerPhone: payload.customerPhone,
-        customerEmail: payload.customerEmail || undefined,
+        customerEmail: payload.customerEmail,
       });
     },
   });