Add FIDO2, WebAuthn and CTAP 2.3 support

[veikkoeeva]

WebAuthn relying party

• Add registration and assertion ceremony verification with clause-level W3C L3 checks.
• Add packed, tpm, android-key, fido-u2f and none attestation verifiers with X.509 chain and profile checks on both crypto backends.
• Add creation and request options builders, extension outputs, appid and related origins handling.
• Add L3 JSON wire readers and envelope carriers.
• Generalize COSE keys into Verifiable.JCose with RSA support.

CTAP 2.3

• Add an authenticator simulator built as a pushdown automaton with injected crypto backends, plus the NFC/APDU transport profile.
• Add makeCredential, getAssertion, getNextAssertion and getInfo with packed self and certified attestation.
• Add clientPIN with PIN/UV auth protocols 1 and 2; HKDF-SHA-256 lands in the cryptography layer.
• Add credentialManagement, authenticatorConfig, reset, bioEnrollment and largeBlobs.
• Add enterprise attestation and the credProtect, minPinLength, largeBlobKey, hmac-secret and hmac-secret-mc extensions.
• Advertise FIDO_2_3 honestly: the section 9 mandatory set is implemented, with every normative clause ledgered (155 implemented and tested, 70 profile conditional, 12 tracked missing of 237 assessed).
• Prove the ceremonies over real wires: APDU transport and a Kestrel-hosted HTTP relying party.
• Certify TPM-resident credential keys through TPM2_Certify against the in-house TPM simulator.

Metadata service

• Add metadata BLOB verification with entry well-formedness guards, serial-number monotonicity and revocation posture seams.
• Add FIDO2 CLI verbs for inspection and metadata work.

OAuth client

• Add token-exchange and JWT-bearer request builders with client secret attach helpers; RFC 8693, RFC 7523 and RFC 6749 section 2.3.1 obligations verified end to end.

Supporting

• Zero secret copies at the provider boundaries and keep wire values in named pooled carriers.
• Widen cryptographic event provenance to every signing surface.
• Move the builder base to Verifiable.Foundation and update Lumoin.Base to 0.0.6.

[github-actions]

Test Results

    1 files      1 suites   5m 17s ⏱️
8 369 tests 8 292 ✅ 77 💤 0 ❌
8 379 runs  8 302 ✅ 77 💤 0 ❌

Results for commit fcd4c30.

♻️ This comment has been updated with latest results.