docs: sync post-golden governance status

[CoderDeltaLAN]

Summary

• Sync docs after governance golden output coverage landed on main.
• Remove the exact test count from README to avoid recurring README churn.
• Document golden contract coverage in CHANGELOG.
• Replace the completed golden-output next phase in the v0.2 spec with a release-readiness follow-up.

Scope

• README.md, CHANGELOG.md, and docs/V0.2-GOVERNANCE-RULES-SPEC.md only.
• No code, tests, fixtures, pyproject, CI, release, tag, license, or dependency changes.
• No version bump and no new maturity/security claims.

Verification

• 94 tests passed locally through ./scripts/check.sh.
• Diff is limited to expected documentation files.
• v0.1.0 tag/release verified intact before push.
• README now points to ./scripts/check.sh and GitHub Actions as the source of truth instead of a fixed test count.