feat(FN-000): create workflow merge work on handoff

Fusion-Task-Id: FN-000

docs/plans/workflow-owned-merge-stack/s07-completion-handoff-merge-work.md

@@ -0,0 +1,46 @@
+---
+title: "S07: completion handoff creates merge work"
+type: refactor
+status: draft-stack-handoff
+date: 2026-06-09
+slice: S07
+milestone: "Runtime"
+origin: docs/plans/2026-06-09-003-refactor-workflow-owned-merge-full-migration-slices-plan.md
+stack_base: feature/workflow-owned-merge-s06-git-merge-capabilities
+---
+
+# S07: completion handoff creates merge work
+
+## Stack Role
+
+This draft PR reserves the S07 review slot in the workflow-owned merge,
+retry, scheduling, and recovery migration stack. It is intentionally a handoff
+artifact, not the completed implementation for this slice.
+
+## Milestone
+
+Runtime
+
+## Depends On
+
+S2 projection, S5 runtime driver, and S6 merge capabilities.
+
+## Goal
+
+Replace task-moved in-review auto-enqueue as policy authority with workflow completion handoff creating merge work.
+
+## Expected File Scope
+
+packages/engine/src/project-engine.ts; packages/engine/src/merger.ts; packages/core/src/store.ts; completion and cutover tests.
+
+## Expected Tests
+
+Coding completion creates merge work, autoMerge false creates manual hold, duplicate handoff idempotency, soft-delete cancellation, startup projection dedupe.
+
+## Exit Gate
+
+New task completions produce workflow merge work before old queue processing runs.
+
+## Full Plan
+
+See `docs/plans/2026-06-09-003-refactor-workflow-owned-merge-full-migration-slices-plan.md`.

packages/core/src/__tests__/merge-request-record.test.ts

@@ -222,4 +222,54 @@ describe("TaskStore merge request record + completion handoff marker", () => {
       lastError: "cancelled-by-user-hard-cancel",
     });
   });
+
+  it("creates idempotent workflow merge work during completion handoff", async () => {
+    const taskId = await createTask();
+    await store.moveTask(taskId, "todo");
+    await store.moveTask(taskId, "in-progress");
+
+    await store.handoffToReview(taskId, {
+      ownerAgentId: "agent-test",
+      evidence: { reason: "fn_task_done", runId: "run-handoff", agentId: "agent-test" },
+      now: "2026-05-30T00:00:00.000Z",
+    });
+    await store.handoffToReview(taskId, {
+      ownerAgentId: "agent-test",
+      evidence: { reason: "fn_task_done", runId: "run-handoff", agentId: "agent-test" },
+      now: "2026-05-30T00:00:01.000Z",
+    });
+
+    expect(store.listWorkflowWorkItemsForTask(taskId, { kinds: ["merge"] })).toEqual([
+      expect.objectContaining({
+        runId: "run-handoff",
+        taskId,
+        nodeId: "merge-gate",
+        kind: "merge",
+        state: "runnable",
+      }),
+    ]);
+  });
+
+  it("creates manual hold workflow work instead of merge work when autoMerge is false", async () => {
+    const taskId = await createTask();
+    await store.updateTask(taskId, { autoMerge: false });
+    await store.moveTask(taskId, "todo");
+    await store.moveTask(taskId, "in-progress");
+
+    await store.handoffToReview(taskId, {
+      ownerAgentId: "agent-test",
+      evidence: { reason: "fn_task_done", runId: "run-manual", agentId: "agent-test" },
+    });
+
+    expect(store.listWorkflowWorkItemsForTask(taskId)).toEqual([
+      expect.objectContaining({
+        runId: "run-manual",
+        taskId,
+        nodeId: "merge-manual-hold",
+        kind: "manual-hold",
+        state: "manual-required",
+        blockedReason: "autoMerge:false",
+      }),
+    ]);
+  });
 });

packages/core/src/store.ts

@@ -6625,6 +6625,11 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
             },
           });
           this.enqueueMergeQueue(id, { priority: task.priority, now: internal.now });
+          this.createCompletionHandoffWorkflowWork(task, {
+            runId: internal.runContext?.runId,
+            now: internal.now,
+            source: internal.evidence?.reason,
+          });
           this.insertRunAuditEventRow({
             taskId: id,
             agentId: internal.runContext?.agentId,
@@ -7092,6 +7097,11 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
       if (internal.fromHandoff) {
         alreadyEnqueued = Boolean(this.db.prepare("SELECT 1 FROM mergeQueue WHERE taskId = ?").get(id));
         this.enqueueMergeQueue(id, { priority: task.priority, now: internal.now });
+        this.createCompletionHandoffWorkflowWork(task, {
+          runId: internal.runContext?.runId,
+          now: internal.now,
+          source: internal.evidence?.reason,
+        });
         this.insertRunAuditEventRow({
           taskId: id,
           agentId: internal.runContext?.agentId,
@@ -9007,6 +9017,38 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
     });
   }
 
+  createCompletionHandoffWorkflowWork(
+    task: Pick<Task, "id" | "autoMerge" | "priority">,
+    opts: { runId?: string; now?: string; source?: string } = {},
+  ): WorkflowWorkItem {
+    const autoMerge = task.autoMerge !== false;
+    const item = this.upsertWorkflowWorkItem({
+      runId: opts.runId ?? `completion-handoff:${task.id}`,
+      taskId: task.id,
+      nodeId: autoMerge ? "merge-gate" : "merge-manual-hold",
+      kind: autoMerge ? "merge" : "manual-hold",
+      state: autoMerge ? "runnable" : "manual-required",
+      blockedReason: autoMerge ? null : "autoMerge:false",
+      now: opts.now,
+    });
+    this.insertRunAuditEventRow({
+      taskId: task.id,
+      runId: item.runId,
+      domain: "database",
+      mutationType: "workflowWorkItem:completion-handoff",
+      target: item.id,
+      metadata: {
+        taskId: task.id,
+        autoMerge,
+        source: opts.source ?? "completion-handoff",
+        workItemId: item.id,
+        nodeId: item.nodeId,
+        state: item.state,
+      },
+    });
+    return item;
+  }
+
   upsertWorkflowWorkItem(input: WorkflowWorkItemUpsertInput): WorkflowWorkItem {
     return this.db.transactionImmediate(() => {
       const existing = this.db