feat(enhanced-kanban): implement group reordering and improve drag-and-drop functionality

- Added support for reordering kanban groups via drag-and-drop, enhancing user experience.
- Updated EnhancedKanbanBoard and EnhancedKanbanGroup components to handle group dragging and state management.
- Introduced visual feedback for dragging groups and tasks, improving usability.
- Refined CSS styles for better layout and responsiveness during drag operations.

worklenz-frontend/src/components/enhanced-kanban/EnhancedKanbanGroup.css

@@ -1,12 +1,15 @@
 .enhanced-kanban-group {
-  min-width: 280px;
-  max-width: 320px;
+  width: 300px;
+  min-width: 300px;
+  max-width: 300px;
   background: var(--ant-color-bg-elevated);
   border-radius: 8px;
   padding: 12px;
   border: 1px solid var(--ant-color-border);
   box-shadow: 0 1px 2px var(--ant-color-shadow);
   transition: all 0.2s ease;
+  display: flex;
+  flex-direction: column;
 }
 
 .enhanced-kanban-group.drag-over {
@@ -15,6 +18,16 @@
   box-shadow: 0 0 0 2px var(--ant-color-primary-border);
 }
 
+.enhanced-kanban-group.group-dragging {
+  opacity: 0.5;
+  z-index: 1000;
+  box-shadow: 0 8px 24px var(--ant-color-shadow);
+}
+
+.enhanced-kanban-group.group-dragging .enhanced-kanban-group-tasks {
+  background: var(--ant-color-bg-elevated);
+}
+
 .enhanced-kanban-group-header {
   display: flex;
   justify-content: space-between;
@@ -22,21 +35,44 @@
   margin-bottom: 12px;
   padding-bottom: 8px;
   border-bottom: 1px solid var(--ant-color-border);
+  cursor: grab;
+  user-select: none;
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  transition: all 0.2s ease;
+  border-radius: 6px;
+  padding: 8px 12px;
+  margin: -8px -8px 4px -8px;
+}
+
+.enhanced-kanban-group-header:active {
+  cursor: grabbing;
 }
 
 .enhanced-kanban-group-header h3 {
   margin: 0;
   font-size: 16px;
   font-weight: 600;
-  color: var(--ant-color-text);
+  color: inherit;
+  text-shadow: 0 1px 2px var(--ant-color-shadow);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  max-width: 180px;
+  display: inline-block;
+  vertical-align: middle;
 }
 
 .task-count {
-  background: var(--ant-color-fill-secondary);
+  background: var(--ant-color-bg-container);
   padding: 2px 8px;
   border-radius: 12px;
   font-size: 12px;
-  color: var(--ant-color-text-secondary);
+  color: var(--ant-color-text);
+  font-weight: 500;
+  border: 1px solid var(--ant-color-border);
+  opacity: 0.8;
 }
 
 .virtualization-indicator {
@@ -62,7 +98,9 @@
   min-height: 200px;
   max-height: 600px;
   transition: all 0.2s ease;
-  overflow: hidden;
+  overflow-y: auto;
+  overflow-x: hidden;
+  background: transparent;
 }
 
 /* Performance optimizations for large lists */
@@ -127,6 +165,42 @@
   color: var(--ant-color-primary);
 }
 
+/* Group drag overlay */
+.group-drag-overlay {
+  background: var(--ant-color-bg-elevated);
+  border: 1px solid var(--ant-color-border);
+  border-radius: 8px;
+  padding: 12px;
+  box-shadow: 0 8px 24px var(--ant-color-shadow);
+  min-width: 280px;
+  max-width: 320px;
+  opacity: 0.9;
+  pointer-events: none;
+  z-index: 1000;
+}
+
+.group-drag-overlay .group-header-content {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.group-drag-overlay h3 {
+  margin: 0;
+  font-size: 16px;
+  font-weight: 600;
+  color: var(--ant-color-text);
+}
+
+.group-drag-overlay .task-count {
+  background: var(--ant-color-bg-container);
+  padding: 2px 8px;
+  border-radius: 12px;
+  font-size: 12px;
+  color: var(--ant-color-text);
+  border: 1px solid var(--ant-color-border);
+}
+
 /* Responsive design for different screen sizes */
 @media (max-width: 768px) {
   .enhanced-kanban-group {
@@ -148,4 +222,23 @@
   .enhanced-kanban-group-tasks {
     max-height: 300px;
   }
+}
+
+.enhanced-kanban-task-card {
+  width: 100%;
+  box-sizing: border-box;
+}
+
+.task-title {
+  font-weight: 500;
+  color: var(--ant-color-text);
+  margin-bottom: 4px;
+  line-height: 1.4;
+  word-break: break-word;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  max-width: 220px;
+  display: inline-block;
+  vertical-align: middle;
 }