feat(fleet): Ship can also merge the linked PR (gh pr merge)

On ship (Ship button / operator action / autoship PATCH), when the run has an open
PR and FLEET_SHIP_MERGES_PR=1, the coordinator squash-merges it via gh (best-effort,
where gh is authed) and marks the run prState=merged. UI button reads 'Ship & merge
PR' when an open PR exists; Ship refreshes runs.

dashboards/tracker-web/src/app/dashboard/fleet/jobs/[id]/page.tsx

@@ -118,8 +118,8 @@ export default function FleetJobDetailPage() {
     if (!job) return;
     setShipping(true);
     try {
-      const updated = await patchJob(jobId, { leaseEpoch: job.leaseEpoch, stage: 'shipped' });
+      await patchJob(jobId, { leaseEpoch: job.leaseEpoch, stage: 'shipped' });
-      setJob(updated);
+      await refresh(); // pull updated job + runs (PR may now be merged)
     } catch {
       /* show error in production */
     } finally {
@@ -197,7 +197,11 @@ export default function FleetJobDetailPage() {
         <div className="flex items-center gap-2">
           {job.stage !== 'shipped' && job.stage !== 'failed' && (
             <Button onClick={handleShip} disabled={shipping} aria-label="Ship this job">
-              {shipping ? 'Shipping...' : 'Ship ✓'}
+              {shipping
+                ? 'Shipping...'
+                : runs.some(r => r.prUrl && r.prState !== 'merged')
+                  ? 'Ship & merge PR ✓'
+                  : 'Ship ✓'}
             </Button>
           )}
           {job.stage === 'building' && (

services/platform-service/src/modules/fleet/coordinator.ts

@@ -18,6 +18,8 @@
  */
 
 import { createHash } from 'node:crypto';
+import { execFile } from 'node:child_process';
+import { promisify } from 'node:util';
 import { BadRequestError, ConflictError } from '../../lib/errors.js';
 import * as repo from './repository.js';
 import {
@@ -633,6 +635,27 @@ async function markLatestRunShipped(jobId: string): Promise<FleetRunDoc | undefi
   return latest;
 }
 
+const execFileAsync = promisify(execFile);
+
+/**
+ * On ship, optionally merge the linked PR via the GitHub CLI (so "Ship" also
+ * lands the code). Opt-in via FLEET_SHIP_MERGES_PR=1 and only where `gh` is
+ * authenticated (the coordinator host). Best-effort: a failure leaves the PR open
+ * and never fails the ship. Marks the run prState=merged on success.
+ */
+async function mergeRunPrOnShip(jobId: string, latest: FleetRunDoc | undefined): Promise<void> {
+  if (process.env.FLEET_SHIP_MERGES_PR !== '1') return;
+  if (!latest?.prUrl || latest.prState === 'merged') return;
+  try {
+    await execFileAsync('gh', ['pr', 'merge', latest.prUrl, '--squash', '--delete-branch'], {
+      timeout: 60_000,
+    });
+    await repo.updateRun(latest.id, jobId, { prState: 'merged' });
+  } catch {
+    // best-effort — leave the PR open if the merge is blocked (checks, conflicts…)
+  }
+}
+
 export async function patchJobFenced(
   jobId: string,
   productId: string,
@@ -670,6 +693,8 @@ export async function patchJobFenced(
     try {
       // Run-level result mirrors the terminal stage (ungated).
       const latest = await markLatestRunShipped(jobId);
+      // Optionally merge the linked PR (flag-gated, best-effort).
+      await mergeRunPrOnShip(jobId, latest);
       // Budgets (flag-gated): accrue the run's actual cost, idempotent per run.
       if (isBudgetsEnabled()) {
         await accrueSpend(productId, latest?.insights?.costUsd ?? 0, `${jobId}:${job.leaseEpoch}`);
@@ -1015,10 +1040,12 @@ export async function operatorAction(
       data: { action, leaseEpoch: newEpoch, returnedTo: stage },
     });
 
-    // Operator `ship` is a terminal success — mirror it onto the run result.
+    // Operator `ship` is a terminal success — mirror it onto the run result and
+    // optionally merge the linked PR (flag-gated, best-effort).
     if (stage === 'shipped') {
       try {
-        await markLatestRunShipped(jobId);
+        const latest = await markLatestRunShipped(jobId);
+        await mergeRunPrOnShip(jobId, latest);
       } catch {
         // best-effort — run bookkeeping never fails the operator action
       }