#938 Workflow result is not the last task's result (test_docker_tools compose_simple/inspect/network_isolation fail)

EARS: When a sequential workflow completes, the workflow result exposed by GET /api/v1/workflows/{id} shall be the result of the final task. Observed 2026-10-15 on image 1c9fbd7f4be3: workflow e0a29ef2 (docker_inspect_test) had all 4 steps succeed (remove_container status=removed) but workflow_completed.result is the inspect_container result. Same for docker_compose_simple (result=compose_up status running) and docker_network_test (result=run_on_network status exited). The 3 tests in tests/integration/test_docker_tools.py fail on this. Not caused by #914 gate: all steps succeeded. Needs a HEAD baseline to confirm it predates #914.