feat: minted keys, VRF seeds, RFC 9162 proofs, history roots, tag URIs and a transparency log

Keys (spec/02 §2.4), the rule paperstack settled on:
- A work key is a Scholar-style citation key, a hyphen and the first four
  Crockford base32 characters of SHA-256("scienting-key/1:" + identity),
  where the identity is the first of doi, arxiv, isbn, pmid, pmcid and
  openalex in same_as, else the folded title, year and family name. A
  collision lengthens the later key by two characters; a key is minted
  once and never recomputed. A document key adds .si, .v<seq> or .<type>
  for versions other than the version of record.
- Every fixture key is now minted (hale2026harmonic-damb,
  okafor2025solvent-acth, writer2027fixed-ynr7.v3, tiny2026tiny-j4qm), so
  every node and record ID was re-minted and the docs rewritten to match.
  The validator checks the document key against the work key and version
  (doc.key.work) and the hash part against the identifier (doc.key.suffix).
  vectors/keys.jsonl pins the cases paperstack's tests pin.

Review:
- Spot-check seeds are ECVRF-EDWARDS25519-SHA512-TAI proofs (RFC 9381),
  implemented in tools/oracle/vrf.py in plain Python and reproduced
  against the RFC's Example 16; the sample ranks by the VRF output. The
  earlier Ed25519 seed could be ground by a dishonest checker.
- RFC 9162 inclusion and consistency proofs (crypto.inclusion_path,
  verify_inclusion, consistency_proof, verify_consistency) with
  scienting-proof/1, vectors/proofs.jsonl and two fixture records.
- document.json carries `history`, the root over the corrections, with
  the empty-tree hash for none (spec/11 §11.5, rule doc.history).
- A provisional transparency log (spec/23): log entries, signed-note
  checkpoints with key hashes as transparency logs share them, the rule
  that a logged revocation beats a self-asserted time, and vectors.
- Reserved signature schemes cose and ml-dsa-65 (spec/08 §8.4).

Identifiers and text:
- urn:scienting: becomes tag:scient.ing,2026: (RFC 4151), since the URN
  namespace was never registered.
- Unicode 16.0 is pinned for normalization and categories (spec/01 §1.4);
  the checker refuses another version.

Checking:
- check.py: keys, proofs, VRF and checkpoint vectors; the proof and
  checkpoint records; a check that every ID and hash the prose quotes
  exists in the fixtures or vectors; three more broken packages
  (history-wrong, key-suffix, key-work).
- stress.py: key, VRF, proof and checkpoint properties.
- Docs: a keys section in the concepts and FAQ, rationale entries for
  keys, VRF, proofs, tag URIs and the Unicode pin, a "Looking ahead"
  section, media-type registration and OCI distribution notes.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/glossary.md

@@ -36,6 +36,10 @@ Checklist
 :   A record of checking an export, such as accessible HTML, against a named standard, criterion by criterion; it is covered by the receipt of the person who checked.
 Format `scienting-checklist/1`, `provisional`. ([8.11](../spec/08-fidelity.md#811-checklists))
 
+Checkpoint
+:   A signed note that states a transparency log's size and root hash, which a verifier checks against the last checkpoint it saw.
+Format `scienting-checkpoint/1`, `provisional`. ([23.2](../spec/23-log.md#232-checkpoints))
+
 Correction
 :   An operation on an established document, with its evidence and author; never edited, only appended. ([11](../spec/11-corrections.md))
 
@@ -45,6 +49,9 @@ Description
 Document
 :   The text established for one version of one work, from one or more witnesses, as a tree of nodes. ([2.1](../spec/02-model.md#21-four-objects), [3](../spec/03-nodes.md))
 
+Document key
+:   The work key, with a dotted suffix for any version other than the version of record: `.si` for Supporting Information, `.v2` for a second preprint. ([2.4](../spec/02-model.md#24-work-and-document-keys))
+
 Drift
 :   The amount that has changed below a container since an anchor on it was made, counted from the corrections: the share of the container's leaves touched by later corrections.
 It is reported as `none`, `low` or `high`, with a default threshold of a quarter. ([6.6](../spec/06-anchors.md#66-drift))
@@ -56,10 +63,13 @@ The key is anchors, a verdict, a chain, a value or planted errors, by exercise k
 Fidelity level
 :   How far a leaf's text was checked against its source, from F0 converted to F3 proofread. ([8.1](../spec/08-fidelity.md#81-levels-of-fidelity))
 
+History root
+:   The root of the Merkle tree over a document's corrections, kept in `document.json`, so a consistency proof can show that a later revision extends an earlier one. ([11.5](../spec/11-corrections.md#115-the-history-root))
+
 JATS
 :   Outside term.
 Journal Article Tag Suite, ANSI/NISO Z39.96-2024, an XML format in which publishers and archives exchange journal content ([the NISO page](https://www.niso.org/publications/z3996-2024-jats)).
-In paperspec, `jats` is a witness kind: the fixture `okafor2025open` was established from a JATS file and a PDF that agree.
+In paperspec, `jats` is a witness kind: the fixture `okafor2025solvent-acth` was established from a JATS file and a PDF that agree.
 The formats ingest JATS and do not replace it. ([2.3](../spec/02-model.md#23-witnessesjson))
 
 Keyed hash
@@ -101,6 +111,10 @@ Policy
 :   A project owner's signed decision that settles rights a record leaves unknown.
 It never overrides a use the record sets to true or false. ([14.2](../spec/14-rights.md#142-effective-uses))
 
+Proof
+:   An RFC 9162 inclusion proof that one item was covered by a receipt, or a consistency proof that one history extends another, each a short list of hashes.
+Format `scienting-proof/1`. ([8.5](../spec/08-fidelity.md#85-merkle-roots))
+
 Project
 :   A team's curated set of documents, with its members, layers, data, reading paths and drafts.
 Format `scienting-project/1`, `provisional`. ([20](../spec/20-projects.md))
@@ -156,6 +170,9 @@ Verdict
 Version
 :   One expression of a work: a preprint, the version of record, an erratum, the Supporting Information. ([2.1](../spec/02-model.md#21-four-objects))
 
+VRF
+:   A verifiable random function (RFC 9381): a keyed function with exactly one valid proof for each key and input, so that a spot-check seed can be checked but not chosen. ([8.8](../spec/08-fidelity.md#88-spot-checks))
+
 Web Annotation
 :   Outside term.
 The W3C Recommendation of 23 February 2017 for annotations with a body, a target and a motivation ([the W3C model](https://www.w3.org/TR/annotation-model/)).
@@ -167,3 +184,6 @@ Witness
 
 Work
 :   A piece of scholarship across all its versions. ([2.1](../spec/02-model.md#21-four-objects))
+
+Work key
+:   A work's permanent name: a Scholar-style citation key, a hyphen, and the first characters of a hash of the work's identity, such as `vaswani2017attention-a241`; minted once and never recomputed. ([2.4](../spec/02-model.md#24-work-and-document-keys))