v0.2.0

Added

• Horus support: clew extract-horus reads a horus-lineage run directory
  and joins edges by content digest, so a graph closes across machines.
• A trigger registry and the generic --trigger kind:value form. An
  unknown kind is read as a label key, so engines that record labels answer
  label queries with no adapter.
• --html on clew impact writes a self-contained impact report.
• The lineage store extractor follows resumed runs: tasks cached from an
  earlier session in the same chain stay in the graph, replaced tasks are
  marked rather than dropped, and an unknown store version is refused.
• A comparison of what each lineage source can prove, in the docs.
• Output sizes in the work-directory extractor.

Changed

• --donor is now --subject. The old flag still works.
• Generic graph queries moved from the domain adapters into core.
• Shipped demo graphs are anonymised.
• The README is a front page. The design documentation moved to docs/.

Fixed

• External inputs that nf-prov crates record as URLs are kept rather than
  dropped.
• The work-directory extractor documents that forwarded files lose their
  producer, and the lineage store is preferred for that reason.