pub fn migrate_legacy_env_vars() -> Vec<(&'static str, &'static str)>Expand description
Backward-compatible environment variable migration.
Maps deprecated ESPRESSO_SEQUENCER_* env vars to their new names.
If a new env var is already set, the old one is ignored. Otherwise the old value is
copied to the new name and a deprecation warning is emitted.
Call this function early in main(), before clap parsing.
Returns the list of migrated (old, new) pairs. Pass to log_migrated_env_vars
after tracing is initialized.