Add layer.yaml, RMASTER-ADR-0009, the consumption contract, and a tracked
non-answer for the five §20.3 questions. Split admission, exposure, and
authorization without renaming schema fields. Finish the workplan.
Assistant: grok
Assistant-Session: 01a04c9f-cd6b-7741-bce0-f1d9d1b3c3bc
Add the exposure contract, additive family schema fields, validator
checks and fixtures, the reef-railiance exception snapshot, and
routed intakes. Enforcement stays in the owning repos.
