Function is_scm_launch_error_code 

pub fn is_scm_launch_error_code(code: Option<i32>) -> bool

True when code is the raw OS error that means “this process wasn’t started by the SCM” – i.e. main should fall back to running the server directly in the foreground rather than treating this as a real failure. Kept as a plain function over the numeric code (rather than matching directly on windows_service::Error, which only exists on Windows) so this small but important piece of “which failure means fall back to console mode” logic is still covered by the cross-platform test run.