Development record

Bare `abcd reading` prints `exclusion rows: 40, asserted into every manifest` (internal/surface/cli/reading.go:439). Manifests carry 30 at detection, 28 at entailment and 31 at widening; the others bind to particular positions, such as comparative (comparativeExclusions, internal/core/reading/include.go:788). So 40 is the table's size. .abcd/development/brief/04-surfaces/23-reading.md:103 says only that the floor rides in every manifest, which holds.