feat(PBI-75): sprint task-edit client-side via workspace-store (#183)

Klik op een taak in het sprint-scherm opent de edit-dialog nu
client-side via setActiveTask op de sprint-workspace-store.
Geen URL-navigatie, geen volledige server re-render — alleen
GET /api/tasks/{id} voor het detail. SSE propageert server-saves
automatisch terug.

- TaskDialog: optionele onClose/onSaved callbacks (closePath
  optional gemaakt — backwards compatible)
- SprintTaskDialogMount: nieuwe client-component die
  selectActiveTask consumeert en TaskDialog rendert
- SprintUrlTaskSync: deeplink (?editTask=<id>) → store
- Sprint page: mounts toegevoegd, editTask searchParam +
  EditTaskLoader-Suspense verwijderd
- TaskList.openEditDialog roept setActiveTask aan ipv router.push
- Vitest integratie-test voor SprintTaskDialogMount

Out-of-scope (follow-up PBIs): newTask-flow, mobile, product-backlog.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/(app)/products/[id]/sprint/[sprintId]/page.tsx

@@ -1,4 +1,3 @@
-import { Suspense } from 'react'
 import { notFound, redirect } from 'next/navigation'
 import { getSession } from '@/lib/auth'
 import { getAccessibleProduct } from '@/lib/product-access'
@@ -9,6 +8,8 @@ import {
   SprintHydrationWrapper,
   type SprintHydrationData,
 } from '@/components/sprint/sprint-hydration-wrapper'
+import { SprintTaskDialogMount } from '@/components/sprint/sprint-task-dialog-mount'
+import { SprintUrlTaskSync } from '@/components/sprint/sprint-url-task-sync'
 import { SyncActiveSprintCookie } from '@/components/sprint/sync-active-sprint-cookie'
 import { SprintSwitcher } from '@/components/shared/sprint-switcher'
 import { getSprintSwitcherData } from '@/lib/sprint-switcher-data'
@@ -18,8 +19,6 @@ import { parsePauseContext } from '@/lib/pause-context'
 import type { SprintStory, PbiWithStories, ProductMember } from '@/components/sprint/sprint-backlog'
 import type { SprintWorkspaceTask } from '@/stores/sprint-workspace/types'
 import { TaskDialog } from '@/app/_components/tasks/task-dialog'
-import { EditTaskLoader } from '@/app/_components/tasks/edit-task-loader'
-import { TaskDialogSkeleton } from '@/app/_components/tasks/task-dialog-skeleton'
 import Link from 'next/link'
 
 interface Props {
@@ -27,13 +26,12 @@ interface Props {
   searchParams: Promise<{
     newTask?: string
     storyId?: string
-    editTask?: string
   }>
 }
 
 export default async function SprintBoardPage({ params, searchParams }: Props) {
   const { id, sprintId } = await params
-  const { newTask, storyId: storyIdParam, editTask } = await searchParams
+  const { newTask, storyId: storyIdParam } = await searchParams
 
   const session = await getSession()
   if (!session.userId) redirect('/login')
@@ -229,6 +227,8 @@ export default async function SprintBoardPage({ params, searchParams }: Props) {
             currentUserId={session.userId}
             members={members}
           />
+          <SprintTaskDialogMount productId={id} isDemo={isDemo} />
+          <SprintUrlTaskSync />
         </SprintHydrationWrapper>
       </div>
 
@@ -246,18 +246,6 @@ export default async function SprintBoardPage({ params, searchParams }: Props) {
           isDemo={isDemo}
         />
       )}
-
-      {editTask && !newTask && (
-        <Suspense fallback={<TaskDialogSkeleton />}>
-          <EditTaskLoader
-            taskId={editTask}
-            userId={session.userId}
-            productId={id}
-            closePath={closePath}
-            isDemo={isDemo}
-          />
-        </Suspense>
-      )}
     </div>
   )
 }

app/_components/tasks/task-dialog.tsx

@@ -60,7 +60,9 @@ interface TaskDialogProps {
   task?: TaskDialogTask
   storyId?: string
   productId: string
-  closePath: string
+  closePath?: string
+  onClose?: () => void
+  onSaved?: (taskId: string) => void
   isDemo?: boolean
 }
 
@@ -81,7 +83,7 @@ const textareaClass = cn(
   'overflow-y-auto',
 )
 
-export function TaskDialog({ task, storyId, productId, closePath, isDemo = false }: TaskDialogProps) {
+export function TaskDialog({ task, storyId, productId, closePath, onClose, onSaved, isDemo = false }: TaskDialogProps) {
   const router = useRouter()
   const [isPending, startTransition] = useTransition()
   const [confirmDelete, setConfirmDelete] = useState(false)
@@ -100,11 +102,12 @@ export function TaskDialog({ task, storyId, productId, closePath, isDemo = false
     },
   })
 
-  function handleClose() {
-    router.push(closePath)
+  function close() {
+    if (onClose) { onClose(); return }
+    if (closePath) router.push(closePath)
   }
 
-  const closeGuard = useDirtyCloseGuard(form.formState.isDirty, handleClose)
+  const closeGuard = useDirtyCloseGuard(form.formState.isDirty, close)
   const handleKeyDown = useDialogSubmitShortcut(() => form.handleSubmit(onSubmit)())
 
   function onSubmit(data: TaskInput) {
@@ -117,7 +120,8 @@ export function TaskDialog({ task, storyId, productId, closePath, isDemo = false
 
       if (result.ok) {
         toast.success(isEdit ? 'Taak opgeslagen' : 'Taak aangemaakt')
-        router.push(closePath)
+        onSaved?.(result.task.id)
+        close()
         return
       }
 
@@ -152,7 +156,7 @@ export function TaskDialog({ task, storyId, productId, closePath, isDemo = false
       const result = await deleteTask(task.id, { productId })
       if (result.ok) {
         toast.success('Taak verwijderd')
-        router.push(closePath)
+        close()
         return
       }
       if (result.code === 403) {