Normalize RUC formatting to base-checkdigit across booking and admin views.

Accept dashed or digits-only RUC input on the backend, store a canonical dashed form, and display it consistently in booking and admin UIs.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/app/(public)/book/[eventId]/_steps/BookingFormStep.tsx

@@ -226,25 +226,10 @@ export function BookingFormStep({
                     onBlur={handleRucBlur}
                     placeholder={t('booking.form.rucPlaceholder')}
                     error={errors.ruc}
-                    inputMode="numeric"
                     maxLength={10}
                     aria-label={t('booking.form.ruc')}
                   />
                 </div>
-
-                <div>
-                  <label className="block text-sm font-medium text-gray-700 mb-1">
-                    {t('booking.form.preferredLanguage')}
-                  </label>
-                  <select
-                    value={formData.preferredLanguage}
-                    onChange={(e) => setFormData({ ...formData, preferredLanguage: e.target.value as 'en' | 'es' })}
-                    className="w-full px-4 py-3 rounded-btn border border-secondary-light-gray focus:outline-none focus:ring-2 focus:ring-primary-yellow"
-                  >
-                    <option value="en">English</option>
-                    <option value="es">Español</option>
-                  </select>
-                </div>
               </div>
             </Card>