Prepare v0.1.30-rc.3 release notes

[ip332]

Summary

• document the additive QBS/BRF inspection and reflection improvements since v0.1.30-rc.2;
• retain the BRF v2 compatibility warning and unchanged epochs/formats;
• document minimal versus reflective QBS, record discovery, canonical identities, and quarry-brf-inspect;
• update current-main validation wording to CTest 53/53;
• align release-version wording with the policy established by PR Clarify release version policy #74.

This PR contains release notes only.

Explicitly not included

• no production code changes;
• no release-script changes;
• no format or compatibility-epoch changes;
• no tag, release artifacts, or publication;
• no PyPI publication.

Exact RC3 artifact reconstruction and publication validation remain post-merge release steps.