0.61.0

Added

• aep.project/4: a tree store that keeps every large value once. Each string of 256 bytes or more, each captured legacy byte string and each record's document is written once to a content-addressed blob directory beside the authority (store.eventlog.blobs, default blobs), and Entity Runtime records its SHA-256 reference in the command, the result, the change and every event instead of the value. Reads resolve every reference before anything above the store sees it, so artifacts, statuses, history, explain and the projection read as they did. A captured legacy journal is kept line by line, each line the blob of the legacy record it is. aep.project/3 stores read and write as before, and a build that predates aep.project/4 refuses the selector before opening a store. Design: docs/design/planning-content-blobs-v0.1.md.
• aep plan store migrate content --engineering <dir> replays an aep.project/3 store into an aep.project/4 one under the same store and stream identities, verifies that every subject, anchor, terminal instance and recorded entry, receipt and position reads equal with references resolved and that every artifact reads equal through the planning contract, and only then replaces the old tree and sets the selector. --keep-source keeps the old tree beside it.
• aep plan artifact validate on an aep.project/4 store reports a blob that does not hash to its name (C1), checks the blob directory for home paths (S9), and skips V2 against a base that selects an earlier version, since the migration writes every authority file anew.