feat(ST-006): voeg restartClaudeJobAction toe aan actions/claude-jobs.ts (#174)

- Exporteert restartClaudeJobAction(jobId) die FAILED/CANCELLED/SKIPPED jobs atomair reset naar QUEUED
- Valideert auth, demo-blokkade, ownership en restartbare status
- Gebruikt prisma.$transaction: claudeJob.updateMany + conditionale sprintTaskExecution.updateMany reset
- Verstuurt pg_notify claude_job_status zodat Jobs-pagina via SSE ververst
- Unit-tests: happy-path (FAILED/CANCELLED/SKIPPED), demo-blokkade, not-found, niet-restartbare status, race-conditie en sprint sub-task reset

actions/claude-jobs.ts

@@ -1,6 +1,7 @@
 'use server'
 
 import { revalidatePath } from 'next/cache'
+import { type ClaudeJobStatus } from '@prisma/client'
 import { prisma } from '@/lib/prisma'
 import { getSession } from '@/lib/auth'
 import { ACTIVE_JOB_STATUSES, jobStatusToApi } from '@/lib/job-status'
@@ -15,6 +16,9 @@ type EnqueueAllResult =
 
 type CancelResult = { success: true } | { error: string }
 
+type RestartResult = { success: true } | { error: string }
+const RESTARTABLE_STATUSES: ClaudeJobStatus[] = ['FAILED', 'CANCELLED', 'SKIPPED']
+
 export type PreviewTask = {
   id: string
   title: string
@@ -109,3 +113,76 @@ export async function cancelClaudeJobAction(jobId: string): Promise<CancelResult
   revalidatePath(`/products/${job.product_id}/solo`)
   return { success: true }
 }
+
+export async function restartClaudeJobAction(jobId: string): Promise<RestartResult> {
+  const session = await getSession()
+  if (!session.userId) return { error: 'Niet ingelogd' }
+  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }
+  if (!jobId) return { error: 'job_id is verplicht' }
+
+  const job = await prisma.claudeJob.findFirst({
+    where: { id: jobId, user_id: session.userId },
+    select: { id: true, status: true, kind: true, task_id: true, idea_id: true, sprint_run_id: true, product_id: true },
+  })
+  if (!job) return { error: 'Job niet gevonden' }
+  if (!RESTARTABLE_STATUSES.includes(job.status)) {
+    return { error: 'Alleen mislukte, geannuleerde of overgeslagen jobs kunnen opnieuw gestart worden' }
+  }
+
+  const updated = await prisma.$transaction(async (tx) => {
+    const result = await tx.claudeJob.updateMany({
+      where: { id: jobId, status: { in: RESTARTABLE_STATUSES } },
+      data: {
+        status: 'QUEUED',
+        retry_count: { increment: 1 },
+        claimed_by_token_id: null,
+        claimed_at: null,
+        started_at: null,
+        finished_at: null,
+        pushed_at: null,
+        verify_result: null,
+        error: null,
+        summary: null,
+        branch: null,
+        head_sha: null,
+        lease_until: null,
+      },
+    })
+    if (result.count === 0) return 0
+    if (job.kind === 'SPRINT_IMPLEMENTATION') {
+      await tx.sprintTaskExecution.updateMany({
+        where: { sprint_job_id: jobId },
+        data: {
+          status: 'PENDING',
+          verify_result: null,
+          verify_summary: null,
+          skip_reason: null,
+          head_sha: null,
+          started_at: null,
+          finished_at: null,
+        },
+      })
+    }
+    return result.count
+  })
+  if (updated === 0) {
+    return { error: 'Job-status is gewijzigd; herlaad en probeer opnieuw' }
+  }
+
+  await prisma.$executeRaw`
+    SELECT pg_notify('scrum4me_changes', ${JSON.stringify({
+      type: 'claude_job_status',
+      job_id: jobId,
+      kind: job.kind,
+      task_id: job.task_id,
+      idea_id: job.idea_id,
+      sprint_run_id: job.sprint_run_id,
+      user_id: session.userId,
+      product_id: job.product_id,
+      status: jobStatusToApi('QUEUED'),
+    })}::text)
+  `
+
+  revalidatePath('/jobs')
+  return { success: true }
+}