The Standard Library as Architecture

UUIDv7 newtypes—HistoryId, RecordId, and HostId—prevent identity domains from mixing while preserving time-ordered generation. RecordIdx expresses sequence position separately from globally unique identity.

Arc<CapClient> shares negotiated server capabilities; Arc<[...]> and owned vectors cross async boundaries without borrowing command-local stacks. Range<RecordIdx> makes packed coverage explicit. Option<RecordIdx> models a missing stream rather than inventing a sentinel index.

RecordStatus is a nested map from hosts and tags to heads. Comparing two immutable summaries produces a deterministic plan before mutation. SQLite transactions then own compound local changes.

Cryptographic keys are owned values loaded from restricted local paths. Each record receives a random content-encryption key wrapped by the master key; metadata becomes authenticated implicit assertion. The server owns ciphertext and ordering metadata, not the ability to inspect shell commands.