Function load_saga_retention_days 

pub fn load_saga_retention_days(
    user_home_dir: &Path,
    log_warn: impl FnMut(&str),
) -> i64

Read <user_home_dir>/config.toml if it exists and return the configured saga retention days, falling back to DEFAULT_SAGA_RETENTION_DAYS on any error. The optional log_warn closure receives a human-readable diagnostic line per failure path (file unreadable / malformed / negative value) so callers can route it through crate::log() without introducing a tracing dep.