feat(M13): auto-PR via gh CLI after successful push (auto_pr=true)

New src/git/pr.ts helper wraps 'gh pr create'; returns { url } or { error }.
maybeCreateAutoPr() in update-job-status checks product.auto_pr, builds title
from story.code + task.title, writes pr_url to DB. Non-fatal: gh failure logs
a warning and leaves DONE status intact. Also syncs schema: auto_pr on Product,
pr_url on ClaudeJob.

src/tools/update-job-status.ts

@@ -13,6 +13,7 @@ import { toolJson, toolError, withToolErrors } from '../errors.js'
 import { removeWorktreeForJob } from '../git/worktree.js'
 import { resolveRepoRoot } from './wait-for-job.js'
 import { pushBranchForJob } from '../git/push.js'
+import { createPullRequest } from '../git/pr.js'
 
 const inputSchema = z.object({
   job_id: z.string().min(1),
@@ -96,6 +97,40 @@ const DB_STATUS_MAP = {
   failed: 'FAILED',
 } as const
 
+export async function maybeCreateAutoPr(opts: {
+  jobId: string
+  productId: string
+  taskId: string
+  worktreePath: string
+  branchName: string
+  summary: string | undefined
+}): Promise<string | null> {
+  const { jobId, productId, taskId, worktreePath, branchName, summary } = opts
+
+  const product = await prisma.product.findUnique({
+    where: { id: productId },
+    select: { auto_pr: true },
+  })
+  if (!product?.auto_pr) return null
+
+  const task = await prisma.task.findUnique({
+    where: { id: taskId },
+    select: { title: true, story: { select: { code: true } } },
+  })
+  if (!task) return null
+
+  const title = task.story.code ? `${task.story.code}: ${task.title}` : task.title
+  const body = summary
+    ? `${summary}\n\n---\n\n*Auto-generated by Scrum4Me agent*`
+    : '*Auto-generated by Scrum4Me agent*'
+
+  const result = await createPullRequest({ worktreePath, branchName, title, body })
+  if ('url' in result) return result.url
+
+  console.warn(`[update_job_status] auto-PR skipped for job ${jobId}:`, result.error)
+  return null
+}
+
 export function registerUpdateJobStatusTool(server: McpServer) {
   server.registerTool(
     'update_job_status',
@@ -149,6 +184,25 @@ export function registerUpdateJobStatusTool(server: McpServer) {
           skipWorktreeCleanup = plan.skipWorktreeCleanup
         }
 
+        // Auto-PR: best-effort, only when push actually happened
+        let prUrl: string | null = null
+        if (actualStatus === 'done' && pushedAt && branchToWrite) {
+          const worktreeDir =
+            process.env.SCRUM4ME_AGENT_WORKTREE_DIR ??
+            path.join(os.homedir(), '.scrum4me-agent-worktrees')
+          prUrl = await maybeCreateAutoPr({
+            jobId: job_id,
+            productId: job.product_id,
+            taskId: job.task_id,
+            worktreePath: path.join(worktreeDir, job_id),
+            branchName: branchToWrite,
+            summary,
+          }).catch((err) => {
+            console.warn(`[update_job_status] auto-PR error for job ${job_id}:`, err)
+            return null
+          })
+        }
+
         const dbStatus = DB_STATUS_MAP[actualStatus as keyof typeof DB_STATUS_MAP]
         const now = new Date()
         const updated = await prisma.claudeJob.update({
@@ -161,12 +215,14 @@ export function registerUpdateJobStatusTool(server: McpServer) {
             ...(pushedAt !== undefined ? { pushed_at: pushedAt } : {}),
             ...(summary !== undefined ? { summary } : {}),
             ...(errorToWrite !== undefined ? { error: errorToWrite } : {}),
+            ...(prUrl !== null ? { pr_url: prUrl } : {}),
           },
           select: {
             id: true,
             status: true,
             branch: true,
             pushed_at: true,
+            pr_url: true,
             summary: true,
             error: true,
             started_at: true,
@@ -190,6 +246,7 @@ export function registerUpdateJobStatusTool(server: McpServer) {
                 status: actualStatus,
                 branch: updated.branch ?? undefined,
                 pushed_at: updated.pushed_at?.toISOString() ?? undefined,
+                pr_url: updated.pr_url ?? undefined,
                 summary: updated.summary ?? undefined,
                 error: updated.error ?? undefined,
               }),
@@ -210,6 +267,7 @@ export function registerUpdateJobStatusTool(server: McpServer) {
           status: actualStatus,
           branch: updated.branch,
           pushed_at: updated.pushed_at?.toISOString() ?? null,
+          pr_url: updated.pr_url ?? null,
           summary: updated.summary,
           error: updated.error,
           started_at: updated.started_at?.toISOString() ?? null,