Constant DEFAULT_AUTH_TOKEN_TTL_SECS 

pub const DEFAULT_AUTH_TOKEN_TTL_SECS: i64 = _; // 25_200i64

Default deadline applied by build_auth_token_for when the caller does not supply one: 7 hours from the current wall clock. Sits inside the venue’s LIGHTER_AUTH_TOKEN_MAX_TTL (8 hours) with an hour of head room so a long-running session can pre-fetch and rotate before expiry.