fix(FN-000): keep workflow processor cleanup best effort

Address PR #1581 feedback by ensuring cleanup transition failures do not hide claimed work identity after runtime dispatch errors.

packages/engine/src/__tests__/workflow-work-engine-dispatch.test.ts

@@ -270,4 +270,42 @@ describe("workflow work processor", () => {
       }),
     ]);
   });
+
+  it("returns claimed identity when runtime and cleanup transition both fail", async () => {
+    const task = await store.createTask({ description: "processor double failure task" });
+    await store.moveTask(task.id, "todo");
+    await store.moveTask(task.id, "in-progress");
+    await store.handoffToReview(task.id, {
+      ownerAgentId: "agent-test",
+      evidence: { reason: "fn_task_done", runId: "run-processor-double-failure", agentId: "agent-test" },
+      now: "2026-06-09T00:00:00.000Z",
+    });
+    const runtime = new WorkflowTaskRuntime({
+      store,
+      primitives: primitives(),
+      runCustomNode: async () => ({ outcome: "success" }),
+    });
+    vi.spyOn(runtime, "runWorkItem").mockRejectedValue(new Error("sqlite busy"));
+    vi.spyOn(store, "transitionWorkflowWorkItem").mockImplementation(() => {
+      throw new Error("cleanup busy");
+    });
+
+    const result = await processDueWorkflowWorkItem(store, runtime, { experimentalFeatures: {} } as any, {
+      now: "2026-06-09T00:00:00.000Z",
+      leaseOwner: "processor-a",
+      leaseDurationMs: 60_000,
+      kinds: workflowMergeWorkKinds(),
+    });
+
+    expect(result).toMatchObject({
+      claimed: true,
+      taskId: task.id,
+      runtime: {
+        disposition: "failed",
+        outcome: "failure",
+        reason: "workflow-work-item-runtime-error:sqlite busy",
+      },
+    });
+    expect(result.workItemId).toBeDefined();
+  });
 });

packages/engine/src/workflow-work-processor.ts

@@ -43,12 +43,16 @@ export async function processDueWorkflowWorkItem(
     runtimeResult = await runtime.runWorkItem(dispatch.workItem, settings);
   } catch (err) {
     const reason = `workflow-work-item-runtime-error:${err instanceof Error ? err.message : String(err)}`;
-    store.transitionWorkflowWorkItem?.(dispatch.workItem.id, "failed", {
-      now: opts.now,
-      leaseOwner: null,
-      leaseExpiresAt: null,
-      lastError: reason,
-    });
+    try {
+      store.transitionWorkflowWorkItem?.(dispatch.workItem.id, "failed", {
+        now: opts.now,
+        leaseOwner: null,
+        leaseExpiresAt: null,
+        lastError: reason,
+      });
+    } catch {
+      // Best-effort cleanup; callers still need the claimed work identity on double-failure.
+    }
     runtimeResult = {
       disposition: "failed",
       outcome: "failure",