feat(PBI-59): Sprint.code (SP-N sequentieel per product)

Voegt een verplicht code-veld toe aan Sprint, sequentieel per product
(consistent met PBI-N, ST-NNN, T-N).

- **Schema** — `Sprint.code String @db.VarChar(30)` + `@@unique([product_id, code])`
- **Migratie** — voegt kolom toe als nullable, backfillt bestaande sprints
  via `ROW_NUMBER() OVER (PARTITION BY product_id ORDER BY created_at)`
  als `SP-N`, en zet daarna NOT NULL + UNIQUE.
- **Generator** — `generateNextSprintCode(productId)` in lib/code-server.ts
  volgt het patroon van story/pbi/task; createSprintAction gebruikt
  `createWithCodeRetry` voor race-bescherming.
- **Seed** — sprint-counter per product (`SP-1`, `SP-2`, ...).

Zichtbaar in:
- Sprint-header (`Product › Sprint actief · SP-3`)
- JobCard + JobDetailPane voor SPRINT_IMPLEMENTATION jobs
- Insights: VelocityChart x-axis (compacter dan goal-truncated),
  AlignmentTrend tooltip, SprintInfoStrip
- actions/jobs-page.ts: `sprintCode` is weer een echte code i.p.v. null

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

actions/jobs-page.ts

@@ -37,7 +37,7 @@ const JOB_INCLUDE = {
   task: { select: { code: true, title: true, description: true, implementation_plan: true } },
   idea: { select: { code: true, title: true, description: true, grill_md: true, plan_md: true } },
   product: { select: { name: true } },
-  sprint_run: { include: { sprint: { select: { sprint_goal: true } } } },
+  sprint_run: { include: { sprint: { select: { sprint_goal: true, code: true } } } },
 } as const
 
 type RawJob = {
@@ -72,7 +72,7 @@ type RawJob = {
     plan_md: string | null
   } | null
   product: { name: string }
-  sprint_run: { sprint: { sprint_goal: string } } | null
+  sprint_run: { sprint: { sprint_goal: string; code: string } } | null
 }
 
 type PriceRow = {
@@ -122,7 +122,7 @@ function mapJob(j: RawJob, priceMap: Map<string, PriceRow>): JobWithRelations {
     ideaCode: j.idea?.code ?? null,
     ideaTitle: j.idea?.title ?? null,
     sprintGoal: j.sprint_run?.sprint.sprint_goal ?? null,
-    sprintCode: null,
+    sprintCode: j.sprint_run?.sprint.code ?? null,
     productName: j.product.name,
     modelId: j.model_id,
     inputTokens: j.input_tokens,

actions/sprints.ts

@@ -13,6 +13,7 @@ import {
 } from '@/lib/schemas/sprint'
 import { enforceUserRateLimit } from '@/lib/rate-limit'
 import { propagateStatusUpwards } from '@/lib/tasks-status-update'
+import { createWithCodeRetry, generateNextSprintCode } from '@/lib/code-server'
 
 async function getSession() {
   return getIronSession<SessionData>(await cookies(), sessionOptions)
@@ -54,15 +55,20 @@ export async function createSprintAction(_prevState: unknown, formData: FormData
   })
   if (existing) return { error: 'Er is al een actieve Sprint voor dit product', sprintId: existing.id, code: 422 }
 
-  const sprint = await prisma.sprint.create({
-    data: {
-      product_id: parsed.data.productId,
-      sprint_goal: parsed.data.sprint_goal,
-      status: 'ACTIVE',
-      start_date: parsed.data.start_date,
-      end_date: parsed.data.end_date,
-    },
-  })
+  const sprint = await createWithCodeRetry(
+    () => generateNextSprintCode(parsed.data.productId),
+    (code) =>
+      prisma.sprint.create({
+        data: {
+          product_id: parsed.data.productId,
+          code,
+          sprint_goal: parsed.data.sprint_goal,
+          status: 'ACTIVE',
+          start_date: parsed.data.start_date,
+          end_date: parsed.data.end_date,
+        },
+      }),
+  )
 
   revalidatePath(`/products/${parsed.data.productId}`)
   return { success: true, sprintId: sprint.id }