refactor(dnd): remove drag-and-drop reorder for stories and tasks

- Remove reorderStoriesAction, reorderTasksAction, reorderSprintStoriesAction
- Delete REST route app/api/stories/[id]/tasks/reorder/route.ts
- Remove DnD from backlog story-panel and task-panel (flat list)
- Remove reorder-within-sprint branch from sprint-board-client handleDragEnd
- Switch SortableSprintRow to plain SprintRow using useDraggable (membership drag kept)
- Remove all DnD from task-list (status toggle + edit kept)
- Remove story-order/task-order/sprint-story-order/sprint-task-order mutation types and store handlers
- Remove related tests for deleted reorder route; fix sprint store tests

components/sprint/task-list.tsx

@@ -1,18 +1,8 @@
 'use client'
 
-import { useState, useTransition } from 'react'
+import { useTransition } from 'react'
 import { useRouter, usePathname } from 'next/navigation'
-import {
-  DndContext, DragEndEvent, DragOverlay,
-  KeyboardSensor, PointerSensor, useSensor, useSensors, closestCenter,
-} from '@dnd-kit/core'
-import {
-  SortableContext, useSortable, verticalListSortingStrategy, arrayMove,
-  sortableKeyboardCoordinates,
-} from '@dnd-kit/sortable'
-import { CSS } from '@dnd-kit/utilities'
 import { Pencil } from 'lucide-react'
-import { toast } from 'sonner'
 import { useShallow } from 'zustand/react/shallow'
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
@@ -25,7 +15,7 @@ import type {
   SprintWorkspaceTask,
   SprintWorkspaceTaskDetail,
 } from '@/stores/sprint-workspace/types'
-import { updateTaskStatusAction, reorderTasksAction } from '@/actions/tasks'
+import { updateTaskStatusAction } from '@/actions/tasks'
 import { DemoTooltip } from '@/components/shared/demo-tooltip'
 import { debugProps } from '@/lib/debug'
 import { cn } from '@/lib/utils'
@@ -53,7 +43,6 @@ const STATUS_LABELS: Record<string, string> = {
   EXCLUDED: 'Uitgesloten',
 }
 
-
 // Behouden voor type-compat met SprintBoardClient props (verdwijnt zodra
 // SprintBoardClient ook geen tasks-prop meer doorgeeft — T-883).
 export interface Task {
@@ -75,7 +64,7 @@ interface TaskListProps {
   isDemo: boolean
 }
 
-function SortableTaskRow({
+function TaskRow({
   task, code, isDemo, onStatusToggle, onEdit,
 }: {
   task: WorkspaceTask
@@ -84,11 +73,8 @@ function SortableTaskRow({
   onStatusToggle: () => void
   onEdit: () => void
 }) {
-  const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({ id: task.id })
-  const style = { transform: CSS.Transform.toString(transform), transition, opacity: isDragging ? 0.4 : 1 }
-
   return (
-    <div ref={setNodeRef} style={style} className="group px-2 py-1">
+    <div className="group px-2 py-1">
       <div
         className={cn(
           'flex items-start gap-2 rounded border border-border px-3 py-2 transition-colors bg-surface-container hover:bg-surface-container-high cursor-pointer',
@@ -105,17 +91,6 @@ function SortableTaskRow({
           }
         }}
       >
-        {!isDemo && (
-          <span
-            {...attributes}
-            {...listeners}
-            onClick={(e) => e.stopPropagation()}
-            className="text-muted-foreground cursor-grab active:cursor-grabbing shrink-0 text-sm select-none mt-0.5"
-            aria-hidden="true"
-          >
-            ⠿
-          </span>
-        )}
         <div className="flex-1 min-w-0">
           <div className="flex items-start justify-between gap-2">
             <p className={cn(
@@ -162,55 +137,12 @@ export function TaskList({ sprintId: _sprintId, productId: _productId, isDemo }:
   const orderedTasks = useSprintWorkspaceStore(
     useShallow(selectTasksForActiveStory),
   )
-  const [activeDragId, setActiveDragId] = useState<string | null>(null)
   const [, startTransition] = useTransition()
   const router = useRouter()
   const pathname = usePathname()
 
-  const taskMap: Record<string, WorkspaceTask> = {}
-  for (const t of orderedTasks) taskMap[t.id] = t
-
   const doneCount = orderedTasks.filter(t => t.status === 'DONE').length
 
-  const sensors = useSensors(
-    useSensor(PointerSensor, { activationConstraint: { distance: 5 } }),
-    useSensor(KeyboardSensor, { coordinateGetter: sortableKeyboardCoordinates }),
-  )
-
-  function handleDragEnd(event: DragEndEvent) {
-    const { active, over } = event
-    if (!storyId) return
-    if (!over || active.id === over.id) return
-    const store = useSprintWorkspaceStore.getState()
-    const prevOrder = [...(store.relations.taskIdsByStory[storyId] ?? [])]
-    const newOrder = arrayMove(
-      [...prevOrder],
-      prevOrder.indexOf(active.id as string),
-      prevOrder.indexOf(over.id as string),
-    )
-
-    const mutationId = store.applyOptimisticMutation({
-      kind: 'sprint-task-order',
-      storyId,
-      prevTaskIds: prevOrder,
-    })
-    useSprintWorkspaceStore.setState((s) => {
-      s.relations.taskIdsByStory[storyId] = newOrder
-    })
-    setActiveDragId(null)
-
-    startTransition(async () => {
-      const result = await reorderTasksAction(storyId, newOrder)
-      const st = useSprintWorkspaceStore.getState()
-      if (result.success) {
-        st.settleMutation(mutationId)
-      } else {
-        st.rollbackMutation(mutationId)
-        toast.error('Volgorde opslaan mislukt')
-      }
-    })
-  }
-
   function handleStatusToggle(task: WorkspaceTask) {
     startTransition(async () => {
       await updateTaskStatusAction(task.id, STATUS_CYCLE[task.status] ?? 'TO_DO')
@@ -263,36 +195,18 @@ export function TaskList({ sprintId: _sprintId, productId: _productId, isDemo }:
             </DemoTooltip>
           </div>
         ) : (
-          <DndContext
-            id="task-list"
-            sensors={sensors}
-            collisionDetection={closestCenter}
-            onDragStart={e => setActiveDragId(e.active.id as string)}
-            onDragEnd={handleDragEnd}
-          >
-            <SortableContext items={orderedTasks.map(t => t.id)} strategy={verticalListSortingStrategy}>
-              {orderedTasks.map((task) => (
-                <SortableTaskRow
-                  key={task.id}
-                  task={task}
-                  code={task.code}
-                  isDemo={isDemo}
-                  onStatusToggle={() => handleStatusToggle(task)}
-                  onEdit={() => openEditDialog(task.id)}
-                />
-              ))}
-            </SortableContext>
-            <DragOverlay>
-              {activeDragId && taskMap[activeDragId] && (
-                <div className={cn(
-                  'rounded border border-primary px-3 py-2 bg-surface-container shadow-lg opacity-90 text-sm',
-                  PRIORITY_BORDER[taskMap[activeDragId].priority],
-                )}>
-                  {taskMap[activeDragId].title}
-                </div>
-              )}
-            </DragOverlay>
-          </DndContext>
+          <>
+            {orderedTasks.map((task) => (
+              <TaskRow
+                key={task.id}
+                task={task}
+                code={task.code}
+                isDemo={isDemo}
+                onStatusToggle={() => handleStatusToggle(task)}
+                onEdit={() => openEditDialog(task.id)}
+              />
+            ))}
+          </>
         )}
       </div>
     </div>