feat(templates/pages/kanban): add drag-and-drop sortable column functionality and improve card movement handling

- New Features: Introduced sortable column UI with drag-and-drop reordering, visual ghost and drag styling, and automatic card movement via API.
- Enhancements: Added CSS classes for ghost and drag effects, integrated htmx `afterSwap` event to reinitialize sortable after dynamic swaps, and improved delay and filter settings.
- Bug Fixes: Fixed column identification logic, ensured proper cleanup of existing sortable instances, and enhanced error handling to reload page on failed moves.

templates/pages/kanban/board_detail.html

@@ -81,6 +81,13 @@
     <label class="modal-backdrop" for="delete-card-modal"></label>
 </div>
 {% endblock %}
+<style>
+    .sortable-ghost { opacity: 0.3; }
+    .sortable-drag {
+        box-shadow: 0 20px 60px rgba(0,0,0,0.2) !important;
+        transform: rotate(3deg) !important;
+    }
+</style>
 {% block extra_scripts %}
 <script>
     function openCardDeleteModal(actionUrl) {
@@ -103,24 +110,39 @@
         return cookieValue;
     }
 
-    document.addEventListener('DOMContentLoaded', function() {
+    function initKanbanSortable() {
         const containers = document.querySelectorAll('[data-sortable-column]');
         const csrftoken = getCookie('csrftoken');
+        if (!csrftoken) return;
 
-        containers.forEach(container => {
-            new Sortable(container, {
-                group: 'shared',
+        containers.forEach(function(container) {
+            if (container.sortableInstance) return;
+
+            container.sortableInstance = new Sortable(container, {
+                group: {
+                    name: 'kanban',
+                    pull: true,
+                    put: true
+                },
                 animation: 150,
-                ghostClass: 'opacity-50',
-                dragClass: '!shadow-xl !rotate-3',
-                delay: 100,
+                ghostClass: 'sortable-ghost',
+                dragClass: 'sortable-drag',
+                delay: 150,
                 delayOnTouchOnly: true,
-                filter: 'button, input, textarea, select, a',
-                preventOnFilter: true,
+                filter: '.no-drag, a, button, input, textarea, select',
+                preventOnFilter: false,
+                scroll: true,
+                bubbleScroll: true,
                 onEnd: function(evt) {
-                    const cardId = evt.item.id.replace('card-', '');
-                    const newColumnId = evt.to.id.replace('column-', '');
-                    const order = evt.newIndex;
+                    var item = evt.item;
+                    var to = evt.to;
+                    if (!item || !to) return;
+
+                    var cardId = item.getAttribute('data-card-id');
+                    var newColumnId = to.getAttribute('data-sortable-column');
+                    var order = evt.newIndex;
+
+                    if (!cardId || !newColumnId || order === undefined) return;
 
                     fetch('/cards/' + cardId + '/move/', {
                         method: 'POST',
@@ -129,12 +151,17 @@
                             'Content-Type': 'application/x-www-form-urlencoded',
                         },
                         body: 'column_id=' + newColumnId + '&order=' + order
-                    }).catch(function(err) {
-                        console.error('Drag drop failed:', err);
+                    }).then(function(r) {
+                        if (!r.ok) location.reload();
+                    }).catch(function() {
+                        location.reload();
                     });
                 }
             });
         });
-    });
+    }
+
+    document.addEventListener('DOMContentLoaded', initKanbanSortable);
+    document.addEventListener('htmx:afterSwap', initKanbanSortable);
 </script>
 {% endblock %}