feat: centralize create/edit flow contexts, extract edit submit service

templates/booking/_participant_form.html.twig

@@ -140,6 +140,12 @@
     </tr>
 {% endmacro %}
 
+{# Shared by booking create and edit flows; callers should pass one of the flow contexts. #}
+{% set bookingFlowContext = bookingEditContext|default(bookingCreateContext|default(null)) %}
+{% set bookingDto = bookingFlowContext.bookingDto %}
+{% set summaryData = bookingFlowContext.summaryData %}
+{% set mutableData = bookingFlowContext.mutableData|default(null) %}
+
 {# Standalone participant form view (replaces main content area) #}
 {% block participant_form %}
     {% form_theme form 'booking/_form_theme.html.twig' %}
@@ -684,7 +690,7 @@
 {% block booking_summary %}
     <div id="booking-summary" hx-swap-oob="innerHTML">
         {% include 'booking/_summary.html.twig' with {
-            'bookingCreateDto': bookingDto,
+            'bookingDto': bookingDto,
             'summaryData': summaryData,
             'mutableData': mutableData|default(null)
         } %}