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>

tools/oracle/db.py

@@ -128,6 +128,7 @@ def load(conn, root, asset_store):
     conn.execute("INSERT OR IGNORE INTO works VALUES (?, ?)", (d["work"]["key"], J(d["work"]["same_as"])))
     ins(conn, "INTO documents", (key, d.get("store"), J(d.get("aliases")), d["kind"], J(d["work"]), J(d["version"]), J(d["relations"]),
          J(d["meta"]), d["language"], J(d.get("license")), d["policy"], J(d["hashing"]), d["root"], d["meta_hash"],
+         d["history"],
          d["rev"], J(d["counts"]), J(d["fidelity"]), J(prov), J(roster), package_hash))
     for i, w in enumerate(read_json(os.path.join(root, "witnesses.json"))["witnesses"]):
         ins(conn, "INTO witnesses", (key, w["id"], i, w["sha256"], w["size"], w["kind"], w["media_type"], w.get("pages"),
@@ -199,7 +200,8 @@ def unload(conn, key, out, asset_store):
                 "meta": P(d["meta"]), "language": d["language"]})
     _opt(doc, "license", P(d["license"]))
     doc.update({"policy": d["policy"], "hashing": P(d["hashing"]), "root": d["root_hash"],
-                "meta_hash": d["meta_hash"], "rev": d["rev"], "counts": P(d["counts"]), "fidelity": P(d["fidelity"])})
+                "meta_hash": d["meta_hash"], "history": d["history"], "rev": d["rev"], "counts": P(d["counts"]),
+                "fidelity": P(d["fidelity"])})
 
     def put(name, rec):
         files[name] = (jcs.dumps(rec) + "\n").encode("utf-8")