keep board horizontal scroll across refresh: restore scrollLeft after #board-container rebuild; v1.0

Template/config/show.php

@@ -12,6 +12,13 @@
         </p>
     </fieldset>
 
+    <fieldset>
+        <?= $this->form->checkbox('organon_tweaks_keep_scroll', t('Keep the board scroll position across refreshes'), 1, isset($values['organon_tweaks_keep_scroll']) && $values['organon_tweaks_keep_scroll'] == 1) ?>
+        <p class="form-help">
+            <?= t('When a card is dropped (or the board auto-refreshes), Kanboard rebuilds the board and jumps back to the first column. This restores the horizontal scroll position so the board stays where you were.') ?>
+        </p>
+    </fieldset>
+
     <div class="form-actions">
         <button type="submit" class="btn btn-blue"><?= t('Save') ?></button>
     </div>