MongrelDB commit-log abstraction and versioned command envelope.
This crate defines the durable-write contract of the engine (spec sections 6.2, 9.3, 9.4):
- [
CommandEnvelope]: the versioned, checksummed, canonically encoded form of every persisted cluster/transaction command. - [
CommitLog]: the single authority through which commands become committed. The storage apply path receives only committed commands.
The standalone adapter (StandaloneCommitLog) lives in mongreldb-core
because it wraps the existing shared WAL; the replicated adapter lands
with the consensus crate in Stage 2.