Function build_braid_config 

pub fn build_braid_config(
    scenario: &Scenario,
    calibration_path: &Path,
    braidz_output_dir: &Path,
    http_api_server_addr: &str,
) -> BraidConfig

Build the in-memory Braid configuration for a scenario: one sim-backed camera per scenario camera, FakeSync at the scenario frame rate, and the given calibration / output directory / control-API address.