feat(PBI-74): sprint-workspace-store (Story 9) (#181)

* feat(PBI-74): sprint-workspace-store skelet (Story 9 / T-879)

- stores/sprint-workspace/{types,store,selectors,restore}.ts conform
  product-workspace blueprint
- ContextSlice: activeProduct, activeSprintId, activeStoryId, activeTaskId
- EntitiesSlice: sprintsById, storiesById, tasksById
- RelationsSlice: sprintIdsByProduct, storyIdsBySprint, taskIdsByStory
- LoadingSlice met activeRequestId voor race-safe ensure*Loaded
- SyncSlice: realtimeStatus, lastResyncAt, resyncReason
- Realtime applyRealtimeEvent voor sprint/story/task entities + unknown-event
  fallback, parent-move handling, child-cleanup bij D op sprint/story
- Optimistic mutations: sprint-story-order, sprint-task-order, entity-patch
- LocalStorage hints (storage key sprint-workspace-hints) per product/sprint
- 45 unit-tests groen — verplicht 13 cases uit workspace-store.md §Tests

* feat(PBI-74): sprint hydratie + realtime SSE (Story 9 / T-880)

- app/api/realtime/sprint/route.ts: SSE-stream LISTEN/NOTIFY op
  scrum4me_changes, filter entity ∈ {sprint, story, task} per product_id;
  ready-event, heartbeat 25s, hard-close 240s
- lib/realtime/use-sprint-realtime.ts: client-hook met backoff-reconnect;
  ready-cycle telt; geen close op hidden; setRealtimeStatus
- lib/realtime/use-sprint-workspace-resync.ts: visibility + online triggers
  resyncActiveScopes('visible' | 'reconnect')
- components/sprint/sprint-hydration-wrapper.tsx: hydrateSnapshot via
  useEffect met fingerprint-check; mount realtime + resync
- app/(app)/products/[id]/sprint/[sprintId]/page.tsx: wrap SprintBoardClient
  in SprintHydrationWrapper; bouw SprintWorkspaceTask-shape voor
  tasksByStoryWorkspace en SprintHydrationData voor de wrapper

Schaduw-fase: useSprintStore blijft parallel werken in board components
totdat T-881 die migreert en T-883 de oude store opruimt.

* feat(PBI-74): migreer sprint-board componenten naar workspace-store (Story 9 / T-881)

- TaskList: leest tasks via selectTasksForStory met useShallow; DnD via
  applyOptimisticMutation('sprint-task-order') + settle/rollback
- SprintBacklogLeft: leest stories via selectStoriesForActiveSprint met
  useShallow; props 'stories' verwijderd
- SprintBoardClient: leest sprintStories uit selector i.p.v. lokale state;
  add/remove via direct setState met manuele snapshot-rollback;
  reorder via applyOptimisticMutation('sprint-story-order'); assignee-
  change via store entity-mutation; tasksByStory en sprintStoryIdList
  props weg
- app/(app)/.../sprint/[sprintId]/page.tsx: bouwt SprintHydrationData voor
  wrapper; geeft alleen non-store props door aan SprintBoardClient

useSprintStore wordt nergens meer geïmporteerd — alleen comment-referentie
in SprintHydrationWrapper. Cleanup van het bestand zelf in T-883.

Verify groen (671 tests, typecheck, lint clean).

* feat(PBI-74): read-routes voor sprint-workspace + cache-headers (Story 9 / T-882)

- GET /api/products/[id]/sprints — lijst sprints per product
  (ensureProductSprintsLoaded). force-dynamic, productAccessFilter,
  start_date/end_date naar ISO-date string.
- GET /api/sprints/[id]/workspace — sprint snapshot met sprint-meta,
  stories (incl. taskCount/doneCount/assignee), tasks gegroepeerd per
  story (ensureSprintLoaded). force-dynamic, productAccessFilter via
  product, status-vertaling via taskStatusToApi/storyStatusToApi.

Race-safe loaders (activeRequestId-guard), restore-flow (cascade-restore
via writeProductHint/writeSprintHint/writeStoryHint/writeTaskHint),
resync-laag (useSprintWorkspaceResync visibility + online), unknown-event
filter (isUnknownEntityEvent → resyncActiveScopes('unknown-event')) zijn
allemaal in T-879/T-880 al ingebouwd; T-882 sluit het loop met de
ontbrekende API-endpoints + cache-headers (cache: 'no-store' op fetches,
force-dynamic op routes).

* feat(PBI-74): cleanup oude sprint-store (Story 9 / T-883)

- rm stores/sprint-store.ts — alle componenten lezen nu via
  useSprintWorkspaceStore (T-881 voltooide imports-migratie)
- update SprintHydrationWrapper-comment: schaduw-fase referenties
  verwijderd

Verify: 671 tests groen, typecheck clean, build groen.
Grep useSprintStore = 0.

* docs(PBI-74): update Story 9 status in implementatieplan (T-884)

- Frontmatter: ready-to-execute → in-progress; revision 1 → 2;
  last_updated 2026-05-09 → 2026-05-10
- Stories-tabel: kolom Status toegevoegd (Stories 1-8 DONE via PR #180,
  Story 9 met T-884 op review)
- §Story 9: per-taak status + acceptatie-checklist voor T-884 manuele
  staging-checks
- Aanbeveling-blokje: noteert dat Story 9 vroeger gestart is dan het
  ontwerpdoc adviseerde

lib/realtime/use-sprint-realtime.ts

@@ -0,0 +1,96 @@
+'use client'
+
+// PBI-74 / Story 9 / T-880: Client hook for the sprint workspace SSE stream.
+// Mounts in SprintHydrationWrapper so it survives Server Action refreshes.
+// Dispatches sprint/story/task change events into useSprintWorkspaceStore.
+//
+// Mirrors use-backlog-realtime.ts:
+// - Stream blijft open op tab hidden — gemiste events worden opgehaald via
+//   resyncActiveScopes('visible') uit useSprintWorkspaceResync.
+// - Latere 'ready'-events (post-reconnect) triggeren
+//   resyncActiveScopes('reconnect') zodat events tijdens disconnect alsnog
+//   binnenkomen.
+
+import { useEffect, useRef } from 'react'
+import { useSprintWorkspaceStore } from '@/stores/sprint-workspace/store'
+
+const BACKOFF_START_MS = 1_000
+const BACKOFF_MAX_MS = 30_000
+
+export function useSprintRealtime(productId: string | null) {
+  const sourceRef = useRef<EventSource | null>(null)
+  const backoffRef = useRef<number>(BACKOFF_START_MS)
+  const reconnectTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const readyCountRef = useRef<number>(0)
+
+  useEffect(() => {
+    if (!productId) return
+
+    const close = () => {
+      if (sourceRef.current) {
+        sourceRef.current.close()
+        sourceRef.current = null
+      }
+      if (reconnectTimerRef.current) {
+        clearTimeout(reconnectTimerRef.current)
+        reconnectTimerRef.current = null
+      }
+    }
+
+    const connect = () => {
+      close()
+      const source = new EventSource(
+        `/api/realtime/sprint?product_id=${encodeURIComponent(productId)}`,
+      )
+      sourceRef.current = source
+      useSprintWorkspaceStore.getState().setRealtimeStatus('connecting')
+
+      source.addEventListener('ready', () => {
+        backoffRef.current = BACKOFF_START_MS
+        readyCountRef.current += 1
+        useSprintWorkspaceStore.getState().setRealtimeStatus('open')
+        if (readyCountRef.current > 1) {
+          void useSprintWorkspaceStore.getState().resyncActiveScopes('reconnect')
+        }
+      })
+
+      source.onmessage = (e) => {
+        if (!e.data) return
+        try {
+          const payload = JSON.parse(e.data) as Record<string, unknown>
+          useSprintWorkspaceStore.getState().applyRealtimeEvent(payload)
+        } catch (err) {
+          if (process.env.NODE_ENV !== 'production') {
+            console.error('[realtime/sprint] failed to parse event', err, e.data)
+          }
+        }
+      }
+
+      source.onerror = () => {
+        if (sourceRef.current !== source) return
+        close()
+        useSprintWorkspaceStore.getState().setRealtimeStatus('disconnected')
+        if (typeof document !== 'undefined' && document.visibilityState === 'hidden') return
+        const delay = backoffRef.current
+        backoffRef.current = Math.min(backoffRef.current * 2, BACKOFF_MAX_MS)
+        reconnectTimerRef.current = setTimeout(connect, delay)
+      }
+    }
+
+    const onVisibility = () => {
+      if (document.visibilityState === 'visible' && sourceRef.current === null) {
+        backoffRef.current = BACKOFF_START_MS
+        connect()
+      }
+    }
+
+    connect()
+    document.addEventListener('visibilitychange', onVisibility)
+
+    return () => {
+      document.removeEventListener('visibilitychange', onVisibility)
+      close()
+      readyCountRef.current = 0
+    }
+  }, [productId])
+}

lib/realtime/use-sprint-workspace-resync.ts

@@ -0,0 +1,36 @@
+'use client'
+
+// PBI-74 / Story 9 / T-880: useSprintWorkspaceResync.
+//
+// Trigger resyncActiveScopes bij:
+// - hidden→visible (browser-throttled events kunnen gemist zijn)
+// - online (netwerk hersteld na disconnect)
+//
+// Hoort gemount te worden naast useSprintRealtime in SprintHydrationWrapper.
+
+import { useEffect } from 'react'
+import { useSprintWorkspaceStore } from '@/stores/sprint-workspace/store'
+
+export function useSprintWorkspaceResync(): void {
+  useEffect(() => {
+    if (typeof document === 'undefined') return
+
+    const onVisibility = () => {
+      if (document.visibilityState === 'visible') {
+        void useSprintWorkspaceStore.getState().resyncActiveScopes('visible')
+      }
+    }
+
+    const onOnline = () => {
+      void useSprintWorkspaceStore.getState().resyncActiveScopes('reconnect')
+    }
+
+    document.addEventListener('visibilitychange', onVisibility)
+    window.addEventListener('online', onOnline)
+
+    return () => {
+      document.removeEventListener('visibilitychange', onVisibility)
+      window.removeEventListener('online', onOnline)
+    }
+  }, [])
+}