The container entrypoint's URI and config branches were mutually
exclusive, so a deployment driven by OMNIGRAPH_TARGET_URI could never
load a policy file. Forward --config alongside the positional URI when
OMNIGRAPH_CONFIG is also set (the URI still wins via resolve_target_uri),
enabling Cedar policy without changing how the URI is provided.
Add docker/entrypoint_test.sh (arg-composition cases) + a CI job, and
document the env-var contract in docs/user/deployment.md.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>