### Reproducible-reconstruction binding — a C2PA/JPEG-Trust hard binding over pixels

- New `wai.*` provenance capability: `reconstruction_binding` (feature
  `provenance`) + [`extensions/reconstruction-binding.md`]. A cryptographic hard
  binding over the *deterministically decoded* pixels of a neural-coded asset —
  which such media normally can't carry, because a neural decode isn't
  reproducible (JPEG AI's normative conformance point is the entropy-decoder
  output, not pixels; its multi-branch design reconstructs one codestream several
  ways). WAI's byte-exact decode restores a portable decoded-pixel hash. SHA-256
  (the C2PA default) over the canonical RGB8 buffer plus a descriptor pinning the
  reproducible decode; carried as a custom C2PA/JPEG-Trust assertion
  (`science.transaction.wai.hash.reconstruction`) beside the standard byte-binding.
  A substrate for machine-readable AI-content marking (e.g. EU AI Act Art. 50).

