The test was calling _handle_git_commit() directly in-process, but the
HERMES_WEBUI_WORKSPACE_GIT_DESTRUCTIVE=1 env var was only being set on the
test_server subprocess (via conftest.py L539). In-process the destructive
gate (returns 403) fires before the active-stream gate (returns 409), so
the test never reached the assertion it was trying to verify.
monkeypatch.setenv() restores the test's intent: confirm that when
destructive mode IS enabled, an active stream still blocks mutations with
the more specific 409 code.
AJV20