ContentHash

type ContentHash = Brand<string, "ContentHash">;

A content-addressed hash of a payload, formatted as <algo>:<hex>.

Current supported algorithms:

• sha256:<64 hex chars>

Meant for content addressing: tamper-evident provenance node content, blob dedup at ingest, memory LogEntry / Fact content hashes.

The prefix is significant: consumers must reject hashes without a recognized algorithm prefix, so future migration to sha3 or blake3 is non-breaking.