feat(tasks): add code field to BacklogTask type and all task selects

Adds `code: string | null` to BacklogTask interface and includes it in
all Prisma task.findMany selects (backlog API, stories tasks API, page
hydration routes). Updates coerceTaskPayload and test fixtures to match.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

__tests__/components/backlog/integration.test.tsx

@@ -71,7 +71,7 @@ const STORIES: BacklogStory[] = [
   { id: STORY_ID, code: 'ST-1', title: 'Eerste story', description: null, acceptance_criteria: null, priority: 2, sort_order: 1, status: 'OPEN', pbi_id: PBI_ID, sprint_id: null, created_at: new Date() },
 ]
 const TASKS: BacklogTask[] = [
-  { id: 'task-1', title: 'Eerste taak', description: null, priority: 2, status: 'TO_DO', sort_order: 1, story_id: STORY_ID, created_at: new Date() },
+  { id: 'task-1', code: null, title: 'Eerste taak', description: null, priority: 2, status: 'TO_DO', sort_order: 1, story_id: STORY_ID, created_at: new Date() },
 ]
 
 function resetStores() {

__tests__/components/backlog/task-panel.test.tsx

@@ -71,8 +71,8 @@ const STORY_ID = 'story-1'
 const CLOSE_PATH = `/products/${PRODUCT_ID}`
 
 const TASKS = [
-  { id: 'task-1', title: 'Eerste taak', description: null, priority: 2, status: 'TO_DO', sort_order: 1, story_id: STORY_ID, created_at: new Date() },
-  { id: 'task-2', title: 'Tweede taak', description: null, priority: 3, status: 'IN_PROGRESS', sort_order: 2, story_id: STORY_ID, created_at: new Date() },
+  { id: 'task-1', code: null, title: 'Eerste taak', description: null, priority: 2, status: 'TO_DO', sort_order: 1, story_id: STORY_ID, created_at: new Date() },
+  { id: 'task-2', code: null, title: 'Tweede taak', description: null, priority: 3, status: 'IN_PROGRESS', sort_order: 2, story_id: STORY_ID, created_at: new Date() },
 ]
 
 function renderPanel(isDemo = false) {

__tests__/stores/product-workspace/store.test.ts

@@ -106,6 +106,7 @@ function makeStory(overrides: Partial<BacklogStory> & { id: string; pbi_id: stri
 function makeTask(overrides: Partial<BacklogTask> & { id: string; story_id: string }): BacklogTask {
   return {
     id: overrides.id,
+    code: overrides.code ?? null,
     title: overrides.title ?? `Task ${overrides.id}`,
     description: overrides.description ?? null,
     priority: overrides.priority ?? 2,

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

@@ -75,6 +75,7 @@ export default async function ProductBacklogPage({ params, searchParams }: Props
       where: { story: { pbi: { product_id: id } } },
       select: {
         id: true,
+        code: true,
         title: true,
         description: true,
         priority: true,

app/(mobile)/m/products/[id]/page.tsx

@@ -61,6 +61,7 @@ export default async function MobileProductBacklogPage({ params, searchParams }:
       where: { story: { pbi: { product_id: id } } },
       select: {
         id: true,
+        code: true,
         title: true,
         description: true,
         priority: true,

app/api/products/[id]/backlog/route.ts

@@ -66,6 +66,7 @@ export async function GET(
       orderBy: [{ sort_order: 'asc' }, { created_at: 'asc' }],
       select: {
         id: true,
+        code: true,
         title: true,
         description: true,
         priority: true,

app/api/stories/[id]/tasks/route.ts

@@ -33,6 +33,7 @@ export async function GET(
     orderBy: [{ sort_order: 'asc' }, { created_at: 'asc' }],
     select: {
       id: true,
+      code: true,
       title: true,
       description: true,
       priority: true,

stores/product-workspace/store.ts

@@ -1039,6 +1039,7 @@ function coerceTaskPayload(id: string, p: Record<string, unknown>): BacklogTask
   const title = p.title ?? p.task_title ?? ''
   return {
     id,
+    code: (p.code as string | null | undefined) ?? null,
     title: String(title),
     description: (p.description as string | null | undefined) ?? null,
     priority: Number(p.priority ?? 4),

stores/product-workspace/types.ts

@@ -27,6 +27,7 @@ export interface BacklogStory {
 
 export interface BacklogTask {
   id: string
+  code: string | null
   title: string
   description: string | null
   priority: number