feat: ML-DSA-65, did:key, named hash algorithm, model provenance, log tiles and witnesses

- hashing.algorithm names the hash function in every document; a consumer refuses one it does not implement (doc.hash.algorithm)
- ML-DSA-65 (FIPS 204) is an implemented signature scheme: pure-Python reference in tools/oracle/mldsa.py checked against NIST ACVP vectors, a receipt signed by the new roster key dana, and signature vectors for key generation and a deterministic signature
- roster keys may carry a did:key, which the validator checks against the public key (doc.roster.did), and a witness purpose for parties that cosign log checkpoints
- model provenance: a correction's author and an annotation's generator name the model with provider, version and the hashes of its weights, prompt and parameters, and where it ran
- the transparency log gains the tlog-tiles static layout (fixtures/records/log/), a project settings.log with origin, witnesses and threshold, and an acceptance rule; the fixture checkpoint is cosigned by a witness
- store.sql: roster_keys accepts cose and ml-dsa-65 and gains a did column
- spec chapters 01, 08, 11, 18, 20 and 23, the rationale, glossary, fixture, vector and tool guides updated; stress harness covers ML-DSA

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

vectors/README.md

@@ -114,7 +114,7 @@ The table below uses a few terms that the chapters define:
 | `keyed.jsonl` | The team key and its ID, an HMAC, page hashes, a page-derived key, and what someone without the paper cannot check. | [5.8](../spec/05-hashes.md#58-keyed-hashes) |
 | `fingerprints.jsonl` | Pages as text lines, the stamp rules that fired, and the fingerprint; two downloads that must agree, and a change that must not. | [7.1](../spec/07-geometry.md#71-page-fingerprints) |
 | `merkle.jsonl` | Receipt items and their Merkle roots. | [8.5](../spec/08-fidelity.md#85-merkle-roots) |
-| `signatures.jsonl` | The RFC 8032 test vector, and a receipt's record hash, signing payload and signature. | [8.4](../spec/08-fidelity.md#84-record-hashes-and-signatures) |
+| `signatures.jsonl` | The RFC 8032 test vector; a receipt's record hash, signing payload and signature; `did:key` identifiers for an Ed25519 and an ML-DSA-65 key; and ML-DSA-65 (FIPS 204): NIST's key-generation case and a deterministic signature. | [8.4](../spec/08-fidelity.md#84-record-hashes-and-signatures) |
 | `spotcheck.jsonl` | Seed payloads, seeds, sample sizes and samples. | [8.8](../spec/08-fidelity.md#88-spot-checks) |
 | `bounds.jsonl` | Reviewer error bounds as reported. | [8.9](../spec/08-fidelity.md#89-reviewer-error-bounds) |
 | `alignment.jsonl` | Two readings of a document, their pairs and their suspects. | [5.6](../spec/05-hashes.md#56-alignment) |
@@ -138,7 +138,7 @@ A candidate format changes only with a recorded reason and a new or changed vect
 
 A passing run shows one thing: for these inputs, your implementation computes the same values as the reference implementation in `tools/oracle/`.
 That code computed the expected outputs, and `pixi run build` regenerates them ([tools/](../tools/README.md)).
-The vectors hold 306 cases in all, some of them small: `hashes.jsonl` has one document, `alignment.jsonl` one pair of readings, `offsets.jsonl` and `signatures.jsonl` two cases each.
+The vectors hold 311 cases in all, some of them small: `hashes.jsonl` has one document, `alignment.jsonl` one pair of readings, `offsets.jsonl` two cases.
 
 The vectors do not show the following.