2879abb355
Adds operator_gate Starlette HTTP middleware that gates every route except an explicit allow-list. Flag defaults OFF so all existing behaviour and tests are unchanged. wire_operator_auth helper in conftest lets tests monkeypatch the module-global SessionLocal and flag, keeping the gate's own DB session pointed at the test engine. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>