Fix booking defaults, dashboard alerts, admin edit flow, and ended-event payments.

Require an explicit payment method on booking, hide stale release banners for past or inactive events, open event editing in place on the detail page, and auto-reject unconfirmed payments after events end without sending email.

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

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

@@ -335,7 +335,7 @@ export function BookingFormStep({
                       <button
                         key={method.id}
                         type="button"
-                        onClick={() => setFormData({ ...formData, paymentMethod: method.id })}
+                        onClick={() => setFormData((prev) => ({ ...prev, paymentMethod: method.id }))}
                         className={`w-full p-4 rounded-lg border-2 transition-all text-left flex items-start gap-4 ${
                           formData.paymentMethod === method.id
                             ? 'border-primary-yellow bg-primary-yellow/10'
@@ -377,6 +377,9 @@ export function BookingFormStep({
                   </>
                 )}
               </div>
+              {errors.paymentMethod && (
+                <p className="mt-3 text-sm text-red-600">{errors.paymentMethod}</p>
+              )}
             </Card>
 
             {/* Terms & Privacy agreement */}
@@ -430,7 +433,7 @@ export function BookingFormStep({
               size="lg"
               className="w-full"
               isLoading={submitting}
-              disabled={paymentMethods.length === 0 || !agreedToTerms}
+              disabled={paymentMethods.length === 0 || !formData.paymentMethod || !agreedToTerms}
             >
               {formData.paymentMethod === 'cash'
                 ? t('booking.form.reserveSpot')