[AIAA] Assessment-quality rubric (pre-pilot gate)

Pre-pilot gate (spec sections 10, 16, 17), not a numbered build step:
the assessment-quality rubric must exist before the pilot's first
deliverable is scored. A pilot scored without it leaves G-2 asserted,
not verified.

Done when:

- [ ] The meta-rubric that scores an assessment's quality is defined,
distinct from `criteria.md`, which scores a project's docs.
- [ ] It is validated by scoring the Flatcar, Knative, and Helm
baseline assessments to set a reference band (sections 2, 10).

This work also sets any post-pilot sampling rule for verification,
replacing the pilot's check-every-finding floor (section 10).