feat(ans): implement @logicsrc/ans M1 — resolver + offline verifier

M1 of the ANS SDK (docs/ans-sdk.md):

- name: parse/format ans://v<semver>.<agent>.<domain>
- cbor: minimal RFC 8949 codec for the COSE_Sign1 subset
- verify/merkle: RFC 6962 leaf/node hashing, tree build, inclusion-proof
  generation + verification
- verify/es256 + cose: COSE_Sign1 build/parse, Sig_structure, ES256 (WebCrypto)
- verify/rootkeys: kid -> verifier key (JWKS entries; sumdb-note is M2)
- verify: verifyReceipt() + verifyResolution() (signature + inclusion proof +
  name binding), pure and offline
- client: AnsClient resolve/rootKeys/register/status over injectable fetch,
  with a DnsApplier hook for verify-dns

Tests (24) cover name parsing, CBOR round-trips/vectors, RFC 6962 proofs, a full
ES256+Merkle receipt round-trip with positive/negative cases, and the client
against mocked fetch. Wired into the root build script.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/ans/src/name.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, it } from 'vitest';
+import { formatAnsName, parseAnsName } from './name.js';
+
+describe('parseAnsName', () => {
+  it('parses a well-formed ans:// name', () => {
+    expect(parseAnsName('ans://v1.0.0.my-agent.example.com')).toEqual({
+      raw: 'ans://v1.0.0.my-agent.example.com',
+      version: '1.0.0',
+      agent: 'my-agent',
+      domain: 'example.com',
+    });
+  });
+
+  it('parses multi-label domains and prerelease versions', () => {
+    const parsed = parseAnsName('ans://v2.3.1-beta.bot.agents.example.co.uk');
+    expect(parsed.version).toBe('2.3.1-beta');
+    expect(parsed.agent).toBe('bot');
+    expect(parsed.domain).toBe('agents.example.co.uk');
+  });
+
+  it.each([
+    'https://v1.0.0.a.example.com',
+    'ans://1.0.0.a.example.com',
+    'ans://v1.0.a.example.com',
+    'ans://v1.0.0.bad agent.example.com',
+    'ans://v1.0.0.agent',
+  ])('rejects malformed name %s', (raw) => {
+    expect(() => parseAnsName(raw)).toThrow();
+  });
+
+  it('round-trips through formatAnsName', () => {
+    expect(formatAnsName({ version: '1.2.3', agent: 'a', domain: 'example.com' })).toBe('ans://v1.2.3.a.example.com');
+  });
+});