feat(PBI-12 T-51): voeg create_sprint tool toe

Maakt een sprint aan met status=OPEN. Code auto-gegenereerd als
S-{YYYY-MM-DD}-{N} per product per datum als niet meegegeven, met retry
bij race-conflict op @@unique([product_id, code]). Volgt create-pbi.ts
template.

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

src/tools/create-sprint.ts

@@ -0,0 +1,124 @@
+// MCP authoring tool: create een Sprint binnen een product.
+//
+// Status start altijd op OPEN; geen reuse-check op bestaande OPEN-sprints
+// (per plan-to-pbi-flow.md "altijd nieuwe sprint"). Code wordt auto-gegenereerd
+// als S-{YYYY-MM-DD}-{N} per product per datum, met retry bij race-condition
+// op de unique constraint (@@unique([product_id, code])).
+
+import { z } from 'zod'
+import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
+import { Prisma } from '@prisma/client'
+import { prisma } from '../prisma.js'
+import { requireWriteAccess } from '../auth.js'
+import { userCanAccessProduct } from '../access.js'
+import { toolError, toolJson, withToolErrors } from '../errors.js'
+
+const SPRINT_AUTO_RE = /^S-(\d{4}-\d{2}-\d{2})-(\d+)$/
+const MAX_CODE_ATTEMPTS = 3
+
+function todayIsoDate(): string {
+  return new Date().toISOString().slice(0, 10)
+}
+
+async function generateNextSprintCode(productId: string): Promise<string> {
+  const today = todayIsoDate()
+  const sprints = await prisma.sprint.findMany({
+    where: { product_id: productId, code: { startsWith: `S-${today}-` } },
+    select: { code: true },
+  })
+  let max = 0
+  for (const s of sprints) {
+    const m = s.code?.match(SPRINT_AUTO_RE)
+    if (m) {
+      const n = Number.parseInt(m[2], 10)
+      if (!Number.isNaN(n) && n > max) max = n
+    }
+  }
+  return `S-${today}-${max + 1}`
+}
+
+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
+  if (!target) return false
+  return Array.isArray(target) ? target.includes('code') : target.includes('code')
+}
+
+const inputSchema = z.object({
+  product_id: z.string().min(1),
+  code: z.string().min(1).max(30).optional(),
+  sprint_goal: z.string().min(1).max(500),
+  start_date: z.string().date().optional(),
+})
+
+export function registerCreateSprintTool(server: McpServer) {
+  server.registerTool(
+    'create_sprint',
+    {
+      title: 'Create Sprint',
+      description:
+        'Create a new sprint for a product with status=OPEN. Code auto-generated as S-{YYYY-MM-DD}-{N} per product per date if not provided. Forbidden for demo accounts.',
+      inputSchema,
+    },
+    async ({ product_id, code, sprint_goal, start_date }) =>
+      withToolErrors(async () => {
+        const auth = await requireWriteAccess()
+        if (!(await userCanAccessProduct(product_id, auth.userId))) {
+          return toolError(`Product ${product_id} not found or not accessible`)
+        }
+
+        const resolvedStartDate = start_date ? new Date(start_date) : new Date()
+
+        if (code) {
+          const sprint = await prisma.sprint.create({
+            data: {
+              product_id,
+              code,
+              sprint_goal,
+              status: 'OPEN',
+              start_date: resolvedStartDate,
+            },
+            select: {
+              id: true,
+              code: true,
+              sprint_goal: true,
+              status: true,
+              start_date: true,
+              created_at: true,
+            },
+          })
+          return toolJson(sprint)
+        }
+
+        let lastError: unknown
+        for (let attempt = 0; attempt < MAX_CODE_ATTEMPTS; attempt++) {
+          const generated = await generateNextSprintCode(product_id)
+          try {
+            const sprint = await prisma.sprint.create({
+              data: {
+                product_id,
+                code: generated,
+                sprint_goal,
+                status: 'OPEN',
+                start_date: resolvedStartDate,
+              },
+              select: {
+                id: true,
+                code: true,
+                sprint_goal: true,
+                status: true,
+                start_date: true,
+                created_at: true,
+              },
+            })
+            return toolJson(sprint)
+          } catch (e) {
+            if (isCodeUniqueConflict(e)) { lastError = e; continue }
+            throw e
+          }
+        }
+        throw lastError ?? new Error('Kon geen unieke sprint-code genereren')
+      }),
+  )
+}