fix: pass BusPro room assignments through on edit

src/Form/Service/ParticipantAssignedRoomFieldHandler.php

@@ -48,6 +48,17 @@ class ParticipantAssignedRoomFieldHandler extends AbstractParticipantFieldHandle
         return 'assignedRoomId';
     }
 
+    /**
+     * Skips edit mode, where room assignments cannot be changed.
+     *
+     * The field is static text there, so a submitted value can only come from a replayed or
+     * hand-crafted POST. The edit request sends the booking's own assignments anyway.
+     */
+    public function shouldProcess(array $submittedData, string $mode, int $participantIndex): bool
+    {
+        return BookingDto::MODE_EDIT !== $mode && parent::shouldProcess($submittedData, $mode, $participantIndex);
+    }
+
     /**
      * Processes the assignedRoomId field for a specific participant.
      *