Function default_output_format 

pub fn default_output_format(app_id: &str) -> String

Computes the default output format for app_id, consulting the ${APP_ID}_OUTPUT env override, the [output].format key in config.toml, and whether stdout is an interactive terminal. Used as the fallback when no explicit --output/--json/--toon/--human is given.

Blocking: this loads config.toml (see ConfigFile::load), performing synchronous filesystem I/O. Cli itself never calls this — it resolves the default from the config already loaded once at Cli::new time instead — but a consumer calling this function directly should avoid doing so from a hot path or within an async executor without spawn_blocking.