I, Pencil verification

Verify an I, Pencil (ipencil-chain) process proof and, optionally, check a file against it. Returns the ipencil-verification/1 result plus `statements`: one pre-scoped sentence per question. There is deliberately NO single valid/invalid verdict — the result answers four separate questions (record unaltered, file matches, time established, authorship) with different strengths of evidence. When reporting to a person, quote the statements rather than summarising them as 'verified'. Offline by default; set checkRegistry to also confirm the proof's registration on Base.

Look up whether a chain head (64 hex chars, the `chain` of a proof's last checkpoint) was published to the I, Pencil registry on Base. With a pointer (the transaction hash a proof carries) this is one exact check at any age. Without one it searches recent blocks only, and a miss means 'not found in the blocks searched', never 'not registered'. A registration records publication by an address, not ownership or authorship.

Reverse lookup: given only an image's 64-bit perceptual hash (16 hex chars), find registry entries whose final fingerprint is EXACTLY that value. Searches recent blocks only (no index exists yet), so a miss is not evidence of absence, and a resized or re-compressed copy may have a slightly different hash and not match. Returns every match: 64-bit hashes can collide, so several works may share one. A match locates a published chain head; obtain and verify that proof before drawing any conclusion.