T3 - conformance tests infrastructure for two revisions #241

Target branch: 2026-07-28-protocol-support

Run 4 conformance steps o CI: client and server, at 2025-11-25 and at 2026-07-28. Rename conformance-baseline.yml to conformance-baseline-2025-11-25.yml, add conformance-baseline-2026-07-28.yml with every scored 2026-07-28 scenario (37 server, 32 client). The sbt conformance task selects the baseline file from the --requirements argument. Update both conformance READMEs with the two-revision commands and the single scenario form --scenario X --spec-version 2026-07-28. The harness version stays at 0.2.0-alpha.11.

Spec:

• Conformance harness README
• Conformance requirement sets

Conformance scenarios that must pass after this task: none new.

Docs: no.