Feature/auditability scoring rubric

[pathankhansalman]

Summary

One or two sentences. What changes and why.

Spec impact

• No change to docs/SPEC.md.
• Editorial change to docs/SPEC.md (no behavioral change).
• Normative change to docs/SPEC.md. List affected sections below.

If this is a normative change, describe:

• What invariant or field is added, removed, or changed.
• Whether previously valid records may now be rejected, or vice versa.
• The corresponding CHANGELOG.md entry.

Validation and testing

• schema/drp.schema.json updated if the machine-checkable shape changed.
• tools/drp_validator.py updated if a new invariant was introduced.
• Positive fixture(s) added under fixtures/valid/.
• Negative fixture(s) added under fixtures/invalid/.
• Tests added or updated under tests/.
• python3 -m pytest tests/ passes locally.

Breaking change?

• No. Strictly additive or editorial.
• Yes. Explain why it is necessary and how consumers migrate.

Checklist

• Branch is up to date with main.
• CHANGELOG.md updated under [Unreleased].
• VERSION updated if this PR cuts a release.
• No new runtime dependencies added to the reference validator.