"keys" was too generic — it collided with the keys local var, the keys.MasterKeys field, and the CLI keys subcommand. Folds in PickOptions→DiscoverOptions and browser/ comment cleanup.
Master-key acquisition and the cross-host dump format are a concern distinct from the raw crypto primitives, so crypto/keyretriever moves to an importable top-level keys/. KeyRetriever→Retriever drops the keys.KeyRetriever stutter.
moonD4rk