aacs::boil was a thin newtype veneer over aacs::derive — a duplicate layer.
Delete it: move the shared key newtypes (Vid, MediaKey, Vuk, ProcessingKey,
UnitKey) into aacs::types, and expose resolve_candidate + KeyCandidate from
aacs::derive directly. Downstream (keysource, disc::encrypt) now import from
aacs::{derive,types}. Pure API consolidation, no behaviour change; full test
suite green on Rust 1.86.
The volume_key module was only 34 lines and is just the tail of the same
DK/PK -> MK -> VUK -> UK derivation ladder as media_key. Fold both into one
derive module so every aacs module is a substantial, distinct responsibility
(crypto/mkb/derive/inf/content/variant/resolve). Relocation only; logic hash
identical (95fb9924); 2210 tests green.
Matthew Jackson