AEP 0.48.0

This tag is not on main. It was cut on a feature branch that was never merged, so 0.49.0 — released after it, from main — does not contain anything below. Everything here reaches the released line in 0.50.0, together with a fix for a defect this release shipped: aep artifact set --model-digest reported success and wrote nothing. Use 0.50.0 or later. The tag is left in place rather than deleted.

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Added

• A lifecycle for executable-system-specification. The kind existed and had no ladder, which
  the engine reads as every status is legal and so is every move — the one kind whose purpose is
  to be held to a generated suite was the one kind nothing held to anything. It now walks
  draft -> validated -> conforming -> superseded -> archived, and conforming costs one
  ess_conformance record so it cannot be asserted into.
• model_digest on a planning artifact, written by aep artifact set --model-digest <hex>.
  ess-conformance already bound a run to the specification revision — a report counts only where
  its spec_digest is the digest the specification records — and the field it reads had nowhere to
  be written, so the requirement failed closed for every adopter and conforming was unreachable.
  Accepted only on a kind that carries a compiled model; refused on any other, by the CLI and by
  the frontmatter validator both, because a write the validator then rejects leaves a document the
  store cannot read.