feat(enhanced-kanban): integrate native drag-and-drop functionality

- Replaced the existing EnhancedKanbanBoard component with EnhancedKanbanBoardNativeDnD to support native drag-and-drop interactions.
- Commented out the previous EnhancedKanbanBoard usage for potential future reference.

worklenz-frontend/src/components/enhanced-kanban/EnhancedKanbanBoardNativeDnD.tsx

@@ -0,0 +1,208 @@
+import React, { useState, useRef, useEffect } from 'react';
+import { useSelector } from 'react-redux';
+import { RootState } from '@/app/store';
+import { ITaskListGroup } from '@/types/tasks/taskList.types';
+import { IProjectTask } from '@/types/project/projectTasksViewModel.types';
+import './EnhancedKanbanBoard.css';
+import './EnhancedKanbanGroup.css';
+import './EnhancedKanbanTaskCard.css';
+
+// Minimal task card for prototype (reuse your styles)
+const TaskCard: React.FC<{
+  task: IProjectTask;
+  onTaskDragStart: (e: React.DragEvent, taskId: string, groupId: string) => void;
+  onTaskDragOver: (e: React.DragEvent, groupId: string, taskIdx: number) => void;
+  onTaskDrop: (e: React.DragEvent, groupId: string, taskIdx: number) => void;
+  groupId: string;
+  isDropIndicator: boolean;
+}> = ({ task, onTaskDragStart, onTaskDragOver, onTaskDrop, groupId, isDropIndicator }) => {
+  const themeMode = useSelector((state: RootState) => state.themeReducer.mode);
+  const background = themeMode === 'dark' ? '#23272f' : '#fff';
+  const color = themeMode === 'dark' ? '#fff' : '#23272f';
+  return (
+    <>
+      {isDropIndicator && (
+        <div style={{ height: 32, margin: '8px 0', background: themeMode === 'dark' ? '#2a2a2a' : '#f0f0f0', borderRadius: 6, border: `2px dashed ${themeMode === 'dark' ? '#555' : '#bbb'}` }} />
+      )}
+      <div
+        className="enhanced-kanban-task-card"
+        draggable
+        onDragStart={e => onTaskDragStart(e, task.id!, groupId)}
+        onDragOver={e => onTaskDragOver(e, groupId, -1)}
+        onDrop={e => onTaskDrop(e, groupId, -1)}
+        style={{ background, color }}
+      >
+        <div className="task-content">
+          <div className="task-title">{task.name}</div>
+          <div className="task-key">{task.task_key}</div>
+          <div className="task-assignees">
+            {task.assignees?.map(a => a.name).join(', ')}
+          </div>
+        </div>
+      </div>
+    </>
+  );
+};
+
+// Minimal group column for prototype
+const KanbanGroup: React.FC<{
+  group: ITaskListGroup;
+  onGroupDragStart: (e: React.DragEvent, groupId: string) => void;
+  onGroupDragOver: (e: React.DragEvent) => void;
+  onGroupDrop: (e: React.DragEvent, groupId: string) => void;
+  onTaskDragStart: (e: React.DragEvent, taskId: string, groupId: string) => void;
+  onTaskDragOver: (e: React.DragEvent, groupId: string, taskIdx: number) => void;
+  onTaskDrop: (e: React.DragEvent, groupId: string, taskIdx: number) => void;
+  hoveredTaskIdx: number | null;
+  hoveredGroupId: string | null;
+}> = ({ group, onGroupDragStart, onGroupDragOver, onGroupDrop, onTaskDragStart, onTaskDragOver, onTaskDrop, hoveredTaskIdx, hoveredGroupId }) => (
+  <div
+    className="enhanced-kanban-group"
+    // Only group header is draggable for group drag
+    >
+    <div
+      className="enhanced-kanban-group-header"
+      draggable
+      onDragStart={e => onGroupDragStart(e, group.id)}
+      onDragOver={onGroupDragOver}
+      onDrop={e => onGroupDrop(e, group.id)}
+    >
+      <h3>{group.name}</h3>
+      <span className="task-count">{group.tasks.length}</span>
+    </div>
+    <div className="enhanced-kanban-group-tasks"
+      onDragOver={e => onTaskDragOver(e, group.id, 0)}
+      onDrop={e => onTaskDrop(e, group.id, 0)}
+    >
+      {/* Drop indicator at the top of the group */}
+      {hoveredGroupId === group.id && hoveredTaskIdx === 0 && (
+        <div className="drop-preview-indicator"><div className="drop-line" /></div>
+      )}
+      {group.tasks.map((task, idx) => (
+        <React.Fragment key={task.id}>
+          <TaskCard
+            task={task}
+            onTaskDragStart={onTaskDragStart}
+            onTaskDragOver={onTaskDragOver}
+            onTaskDrop={onTaskDrop}
+            groupId={group.id}
+            isDropIndicator={hoveredGroupId === group.id && hoveredTaskIdx === idx + 1}
+          />
+        </React.Fragment>
+      ))}
+      {/* Drop indicator at the end of the group */}
+      {hoveredGroupId === group.id && hoveredTaskIdx === group.tasks.length && (
+        <div className="drop-preview-indicator"><div className="drop-line" /></div>
+      )}
+    </div>
+  </div>
+);
+
+const EnhancedKanbanBoardNativeDnD: React.FC<{ projectId: string }> = ({ projectId }) => {
+  // Get initial groups from Redux
+  const reduxGroups = useSelector((state: RootState) => state.enhancedKanbanReducer.taskGroups);
+  // Local state for groups/tasks
+  const [groups, setGroups] = useState<ITaskListGroup[]>([]);
+  // Drag state
+  const [draggedGroupId, setDraggedGroupId] = useState<string | null>(null);
+  const [draggedTaskId, setDraggedTaskId] = useState<string | null>(null);
+  const [draggedTaskGroupId, setDraggedTaskGroupId] = useState<string | null>(null);
+  const [hoveredGroupId, setHoveredGroupId] = useState<string | null>(null);
+  const [hoveredTaskIdx, setHoveredTaskIdx] = useState<number | null>(null);
+  const [dragType, setDragType] = useState<'group' | 'task' | null>(null);
+
+  // Sync local state with Redux on mount or when reduxGroups or projectId change
+  useEffect(() => {
+    setGroups(reduxGroups.map(g => ({ ...g, tasks: [...g.tasks] })));
+  }, [reduxGroups, projectId]);
+
+  // Group drag handlers
+  const handleGroupDragStart = (e: React.DragEvent, groupId: string) => {
+    setDraggedGroupId(groupId);
+    setDragType('group');
+    e.dataTransfer.effectAllowed = 'move';
+  };
+  const handleGroupDragOver = (e: React.DragEvent) => {
+    if (dragType !== 'group') return;
+    e.preventDefault();
+  };
+  const handleGroupDrop = (e: React.DragEvent, targetGroupId: string) => {
+    if (dragType !== 'group') return;
+    e.preventDefault();
+    if (!draggedGroupId || draggedGroupId === targetGroupId) return;
+    const updated = [...groups];
+    const fromIdx = updated.findIndex(g => g.id === draggedGroupId);
+    const [moved] = updated.splice(fromIdx, 1);
+    const toIdx = updated.findIndex(g => g.id === targetGroupId);
+    updated.splice(toIdx, 0, moved);
+    setGroups(updated);
+    setDraggedGroupId(null);
+    setDragType(null);
+  };
+
+  // Task drag handlers
+  const handleTaskDragStart = (e: React.DragEvent, taskId: string, groupId: string) => {
+    setDraggedTaskId(taskId);
+    setDraggedTaskGroupId(groupId);
+    setDragType('task');
+    e.dataTransfer.effectAllowed = 'move';
+  };
+  const handleTaskDragOver = (e: React.DragEvent, groupId: string, taskIdx: number) => {
+    if (dragType !== 'task') return;
+    e.preventDefault();
+    if (draggedTaskId) {
+      setHoveredGroupId(groupId);
+      setHoveredTaskIdx(taskIdx);
+    }
+  };
+  const handleTaskDrop = (e: React.DragEvent, targetGroupId: string, targetTaskIdx: number) => {
+    if (dragType !== 'task') return;
+    e.preventDefault();
+    if (!draggedTaskId || !draggedTaskGroupId || hoveredGroupId === null || hoveredTaskIdx === null) return;
+    const updated = [...groups];
+    const sourceGroup = updated.find(g => g.id === draggedTaskGroupId);
+    const targetGroup = updated.find(g => g.id === targetGroupId);
+    if (!sourceGroup || !targetGroup) return;
+    // Remove from source
+    const taskIdx = sourceGroup.tasks.findIndex(t => t.id === draggedTaskId);
+    if (taskIdx === -1) return;
+    const [movedTask] = sourceGroup.tasks.splice(taskIdx, 1);
+    // Insert into target at the correct index
+    let insertIdx = targetTaskIdx;
+    if (sourceGroup.id === targetGroup.id && taskIdx < insertIdx) {
+      insertIdx--;
+    }
+    if (insertIdx < 0) insertIdx = 0;
+    if (insertIdx > targetGroup.tasks.length) insertIdx = targetGroup.tasks.length;
+    targetGroup.tasks.splice(insertIdx, 0, movedTask);
+    setGroups(updated);
+    setDraggedTaskId(null);
+    setDraggedTaskGroupId(null);
+    setHoveredGroupId(null);
+    setHoveredTaskIdx(null);
+    setDragType(null);
+  };
+
+  return (
+    <div className="enhanced-kanban-board">
+      <div className="kanban-groups-container">
+        {groups.map(group => (
+          <KanbanGroup
+            key={group.id}
+            group={group}
+            onGroupDragStart={handleGroupDragStart}
+            onGroupDragOver={handleGroupDragOver}
+            onGroupDrop={handleGroupDrop}
+            onTaskDragStart={handleTaskDragStart}
+            onTaskDragOver={handleTaskDragOver}
+            onTaskDrop={handleTaskDrop}
+            hoveredTaskIdx={hoveredGroupId === group.id ? hoveredTaskIdx : null}
+            hoveredGroupId={hoveredGroupId}
+          />
+        ))}
+      </div>
+    </div>
+  );
+};
+
+export default EnhancedKanbanBoardNativeDnD; 

worklenz-frontend/src/pages/projects/projectView/enhancedBoard/project-view-enhanced-board.tsx

@@ -1,6 +1,7 @@
 import React from 'react';
 import { useAppSelector } from '@/hooks/useAppSelector';
 import EnhancedKanbanBoard from '@/components/enhanced-kanban/EnhancedKanbanBoard';
+import EnhancedKanbanBoardNativeDnD from '@/components/enhanced-kanban/EnhancedKanbanBoardNativeDnD';
 
 const ProjectViewEnhancedBoard: React.FC = () => {
   const { project } = useAppSelector(state => state.projectReducer);
@@ -15,7 +16,8 @@ const ProjectViewEnhancedBoard: React.FC = () => {
 
   return (
     <div className="project-view-enhanced-board">
-      <EnhancedKanbanBoard projectId={project.id} />
+      {/* <EnhancedKanbanBoard projectId={project.id} /> */}
+      <EnhancedKanbanBoardNativeDnD projectId={project.id} />
     </div>
   );
 };