is_artefact?

[matt-beanland]

Add is_artefact? to the API. Likely this would be part of behaviour in future.

[matt-beanland]

#27 — is_artefact? (closed in 0.1.5)

Added Artefact.is_artefact?/1:

Artefact.is_artefact?(%Artefact{})  # true
Artefact.is_artefact?(%{})          # false

Cheap struct-shape predicate, separate from is_valid?/1 which does
the deeper structural rule check.

In 0.2.0 it lives in Artefact.Validator and is delegated through
the Artefact facade — callers don't see the move.