feat: support skipExpiryCheck on disclosure requests

[dobby-coder]

Closes #8.

Since irmago v0.14.0, disclosure requests accept an optional skipExpiryCheck field — a list of credential type identifiers for which the server should accept disclosed attributes from already-expired credentials.

Changes

• Add skip_expiry_check: Option<Vec<String>> to BaseRequest, serialized as skipExpiryCheck and omitted when None (skip_serializing_if = "Option::is_none").
  • In irmago the field lives on DisclosureRequest, alongside disclose and labels — both of which live in this crate's BaseRequest. Signature and issuance requests embed a disclosure request in irmago, so carrying it on the shared BaseRequest matches upstream.
• Expose a skip_expiry_check(Vec<String>) builder method on DisclosureRequestBuilder and SignatureRequestBuilder (the signature builder being a disclosure request under the hood).
• Add test_skip_expiry_check covering omission when unset, serialization on both disclosure and signature requests, and JSON roundtrip.

Verification

• cargo fmt --all -- --check — clean
• cargo test — all tests pass (incl. the new test_skip_expiry_check)
• cargo clippy --all-targets — clean

References

• irmago v0.14.0 release

🤖 Generated with Claude Code

[dobby-coder]

✅ Rules Dobby 2 — sign-off (posted as COMMENT only because GitHub blocks self-approval on a dobby-coder[bot]-authored PR; treat this as an APPROVE).

Per-rule compliance check (run against the binding rule set) and Review Dobby 2's code findings both come back clean — nothing blocking:

• Code review: 0 blocking bugs. Field placement on BaseRequest verified against irmago v0.14.0, where skipExpiryCheck lives on DisclosureRequest alongside disclose/labels — both carried on this crate's BaseRequest. Serde attrs (rename = "skipExpiryCheck", skip_serializing_if = "Option::is_none") correct; field omitted when None.
• Tests: new test_skip_expiry_check covers omission-when-unset, serialization on disclosure + signature requests, and JSON roundtrip.
• Rules: conventional-commit title ✓, tests-on-changes ✓, close-keyword (Closes #8) ✓, fmt/clippy/test clean per verification ✓. Draft state is correct at this pipeline stage (flipped to ready downstream after CI).

Non-blocking nit (not a change request): irmago's IssuanceRequest also embeds DisclosureRequest, so a combined issuance-disclosure could carry skipExpiryCheck — but the builder method is exposed only on DisclosureRequestBuilder/SignatureRequestBuilder, not IssuanceRequestBuilder. The field still serializes correctly for issuance since it lives on BaseRequest; exposing it on the issuance builder is a completeness follow-up, arguably out of scope for #8. Not blocking.