feat(codes): generateNextTaskCode + CODE_REGEX export + Zod regex op alle 3 schemas

- lib/code.ts: rename VALID_CODE_RE naar geexporteerde CODE_REGEX,
  verwijder ongebruikte deriveTaskCode
- lib/code-server.ts: generateNextTaskCode(productId) — flat per-product
  T-N teller, hergebruikt nextSequential helper. Export
  isCodeUniqueConflict zodat callers P2002 op code-veld kunnen detecteren
- Zod schemas (pbi/story/task): codeField met trim + max-length + regex,
  optional input (server vult bij ontbreken). Task krijgt voor het
  eerst een codeField

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

lib/code-server.ts

@@ -3,7 +3,7 @@ import { prisma } from '@/lib/prisma'
 
 const MAX_AUTO_CODE_ATTEMPTS = 3
 
-function isCodeUniqueConflict(error: unknown): boolean {
+export function isCodeUniqueConflict(error: unknown): boolean {
   if (!(error instanceof Prisma.PrismaClientKnownRequestError)) return false
   if (error.code !== 'P2002') return false
   const target = (error.meta as { target?: string[] | string } | undefined)?.target
@@ -40,6 +40,7 @@ export async function createWithCodeRetry<T>(
 
 const STORY_AUTO_RE = /^ST-(\d+)$/
 const PBI_AUTO_RE = /^PBI-(\d+)$/
+const TASK_AUTO_RE = /^T-(\d+)$/
 
 function nextSequential(existing: (string | null)[], pattern: RegExp): number {
   let max = 0
@@ -71,3 +72,13 @@ export async function generateNextPbiCode(productId: string): Promise<string> {
   const next = nextSequential(pbis.map((p) => p.code), PBI_AUTO_RE)
   return `PBI-${next}`
 }
+
+export async function generateNextTaskCode(productId: string): Promise<string> {
+  const tasks = await prisma.task.findMany({
+    where: { product_id: productId },
+    select: { code: true },
+  })
+  const next = nextSequential(tasks.map((t) => t.code), TASK_AUTO_RE)
+  return `T-${next}`
+}
+

lib/code.ts

@@ -1,12 +1,12 @@
 // Pure helpers — safe to import from client components.
 // DB-backed helpers (generateNextStoryCode/PbiCode) live in lib/code-server.ts.
 
-const VALID_CODE_RE = /^[A-Za-z0-9._-]+$/
+export const CODE_REGEX = /^[A-Za-z0-9._-]+$/
 
 export const MAX_CODE_LENGTH = 30
 
 export function isValidCode(code: string): boolean {
-  return code.length > 0 && code.length <= MAX_CODE_LENGTH && VALID_CODE_RE.test(code)
+  return code.length > 0 && code.length <= MAX_CODE_LENGTH && CODE_REGEX.test(code)
 }
 
 export function normalizeCode(input: string | null | undefined): string | null {
@@ -14,8 +14,3 @@ export function normalizeCode(input: string | null | undefined): string | null {
   const trimmed = input.trim()
   return trimmed === '' ? null : trimmed
 }
-
-export function deriveTaskCode(storyCode: string | null, indexOneBased: number): string | null {
-  if (!storyCode) return null
-  return `${storyCode}.${indexOneBased}`
-}

lib/schemas/pbi.ts

@@ -1,7 +1,13 @@
 import { z } from 'zod'
-import { MAX_CODE_LENGTH } from '@/lib/code'
+import { CODE_REGEX, MAX_CODE_LENGTH } from '@/lib/code'
 
-const codeField = z.string().max(MAX_CODE_LENGTH).optional()
+const codeField = z
+  .string()
+  .trim()
+  .max(MAX_CODE_LENGTH)
+  .regex(CODE_REGEX, 'Ongeldige code')
+  .optional()
+  .or(z.literal(''))
 const statusField = z.enum(['ready', 'blocked', 'done']).optional()
 
 export const createPbiSchema = z.object({

lib/schemas/story.ts

@@ -1,7 +1,13 @@
 import { z } from 'zod'
-import { MAX_CODE_LENGTH } from '@/lib/code'
+import { CODE_REGEX, MAX_CODE_LENGTH } from '@/lib/code'
 
-const codeField = z.string().max(MAX_CODE_LENGTH).optional()
+const codeField = z
+  .string()
+  .trim()
+  .max(MAX_CODE_LENGTH)
+  .regex(CODE_REGEX, 'Ongeldige code')
+  .optional()
+  .or(z.literal(''))
 
 export const createStorySchema = z.object({
   pbiId: z.string(),

lib/schemas/task.ts

@@ -1,7 +1,15 @@
 import { z } from 'zod'
 import { TaskStatus } from '@prisma/client'
+import { CODE_REGEX, MAX_CODE_LENGTH } from '@/lib/code'
 
 export const taskSchema = z.object({
+  code: z
+    .string()
+    .trim()
+    .max(MAX_CODE_LENGTH)
+    .regex(CODE_REGEX, 'Ongeldige code')
+    .optional()
+    .or(z.literal('')),
   title: z.string().trim().min(1, 'Verplicht').max(120),
   description: z.string().max(2000).optional(),
   implementation_plan: z.string().max(10000).optional(),