fix: never validate insurance selection in edit mode

src/Form/Model/ParticipantEditDto.php

@@ -32,12 +32,21 @@ class ParticipantEditDto
      * the insurance field is hidden and will be automatically assigned by the bulk
      * insurance handler.
      *
+     * In edit mode, this validation is skipped entirely because insurance data is
+     * readonly and preserved as-is from the BPN API (the insurance field handler
+     * does not process insurance in edit mode).
+     *
      * This validation only runs when strict_required group is active.
      */
     #[Assert\Callback(groups: ['strict_required'])]
     public function validateInsuranceRequired(ExecutionContextInterface $context): void
     {
-        // Insurance is always required for applicant
+        // Skip validation in edit mode - insurance is readonly and preserved as-is
+        if (BookingDto::MODE_EDIT === $this->bookingContext->getMode()) {
+            return;
+        }
+
+        // Insurance is always required for applicant in create mode
         if (true === $this->participant->isApplicant()) {
             if (null === $this->participant->insurance) {
                 $context->buildViolation('Bitte auswählen')