Function app_id_env_prefix 

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

Sanitizes an app id into an environment-variable prefix: ASCII alphanumerics are uppercased and every other character becomes _, e.g. godaddy -> GODADDY, my-cli -> MY_CLI.

Shared by the framework’s app-scoped env vars (for example output_env_var and ${PREFIX}_CREDENTIAL_STORE) so they derive the same prefix from a given app id.