feat(booking): add validation to prevent past bookings and implement slot validation logic

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

@@ -1,6 +1,7 @@
 import { randomInt } from 'node:crypto';
 import { CourtBookingStatus } from '@/generated/prisma/enums';
 import { db } from '@/lib/prisma';
+import { isSlotInPast } from '@/lib/slot-validator';
 import { evaluatePlanUsage, parsePlanRules } from '@/modules/plan/services/plan-rules.service';
 import type { DayOfWeek } from '@repo/api-contract';
 import type {
@@ -361,6 +362,10 @@ export async function createAdminBooking(
     );
   }
 
+  if (isSlotInPast(bookingDate, input.startTime, court.slotDurationMinutes)) {
+    throw new AdminBookingServiceError('No se pueden crear reservas en el pasado.', 400);
+  }
+
   for (let attempt = 0; attempt < 5; attempt += 1) {
     try {
       const booking = await db.$transaction(async (tx) => {