feat: unique email addresses of participants unless child, cleanup

addresses #869axbn21

src/Service/BookingService.php

@@ -149,7 +149,7 @@ class BookingService
      * Persists the current booking state to the session for retrieval
      * across multiple HTTP requests during the booking flow.
      *
-     * @param Request          $request          The HTTP request with session
+     * @param Request    $request          The HTTP request with session
      * @param BookingDto $bookingCreateDto The booking DTO to persist
      */
     public function saveBookingCreateDto(Request $request, BookingDto $bookingCreateDto): void
@@ -416,7 +416,7 @@ class BookingService
      * Compares the current room selection state with a baseline snapshot
      * to detect changes that would require participant reassignment.
      *
-     * @param array            $oldSnapshot The baseline room selection snapshot
+     * @param array      $oldSnapshot The baseline room selection snapshot
      * @param BookingDto $newDto      The current booking DTO
      *
      * @return bool True if room selections have changed, false otherwise