fix(helpdesk): user-select as multi-select, store as JSON array

- select multiple, no placeholder option (was causing two empty entries)
- value stored as JSON array string e.g. ["1","3"]
- on render decode JSON back to array for selected check
- both create and edit actions read field as array

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

modules/helpdesk/pages/helpdesk/handovers/_form.phtml

@@ -58,6 +58,13 @@ $hasDiff = $fieldDiff !== [];
       </div>
 
     <?php elseif ($type === 'user-select'): ?>
+      <?php
+        $selectedIds = [];
+        if ($value !== '') {
+            $decoded = json_decode($value, true);
+            $selectedIds = is_array($decoded) ? array_map('strval', $decoded) : [$value];
+        }
+      ?>
       <div class="handover-diff-field<?php e($diffClass); ?>">
         <label for="<?php e($inputId); ?>">
           <?php e($label); ?>
@@ -65,18 +72,19 @@ $hasDiff = $fieldDiff !== [];
         </label>
         <select
           id="<?php e($inputId); ?>"
-          name="field_<?php e($key); ?>"
+          name="field_<?php e($key); ?>[]"
+          multiple
+          size="5"
           <?php if ($required): ?> aria-required="true"<?php endif; ?>
           <?php if ($readonly): ?> disabled<?php endif; ?>
         >
-          <option value=""><?php e(t('Please select...')); ?></option>
           <?php foreach ($tenantUsers as $u):
               $uId = (string) ($u['id'] ?? '');
               $uName = trim((string) ($u['display_name'] ?? ''));
               $uEmail = (string) ($u['email'] ?? '');
               $uLabel = $uName !== '' ? $uName : $uEmail;
           ?>
-            <option value="<?php e($uId); ?>"<?php if ($value === $uId): ?> selected<?php endif; ?>>
+            <option value="<?php e($uId); ?>"<?php if (in_array($uId, $selectedIds, true)): ?> selected<?php endif; ?>>
               <?php e($uLabel); ?>
             </option>
           <?php endforeach; ?>

modules/helpdesk/pages/helpdesk/handovers/create().php

@@ -261,6 +261,9 @@ if ($step === $protocolStep) {
             $type = $field['type'] ?? 'text';
             if ($type === 'checkbox') {
                 $fieldValues[$key] = $request->body('field_' . $key, '') !== '' ? '1' : '0';
+            } elseif ($type === 'user-select') {
+                $ids = $request->body('field_' . $key, []);
+                $fieldValues[$key] = json_encode(array_values(array_filter((array) $ids)));
             } else {
                 $fieldValues[$key] = (string) $request->body('field_' . $key, '');
             }

modules/helpdesk/pages/helpdesk/handovers/edit($id).php

@@ -148,6 +148,9 @@ if ($request->isMethod('POST') && $canEdit) {
         $type = $field['type'] ?? 'text';
         if ($type === 'checkbox') {
             $submittedValues[$key] = $request->body('field_' . $key, '') !== '' ? '1' : '0';
+        } elseif ($type === 'user-select') {
+            $ids = $request->body('field_' . $key, []);
+            $submittedValues[$key] = json_encode(array_values(array_filter((array) $ids)));
         } else {
             $submittedValues[$key] = (string) $request->body('field_' . $key, '');
         }