C4 + H7: the in-concert layer, and the disjunct Stage 7 never measured

Workstream C4 was registered six times in the experiment log and never
once produced a result; the two existing harnesses report solo AUC only.
This is the missing layer, and it is committed rather than run from a
scratchpad so the numbers are reproducible.

Method: rank-AUC with cluster-bootstrap bands computed from THAT
comparison's n; frozen (unfitted) rank-sum as the in-concert combiner,
so the ensemble leaks no labels; marginal value as a PAIRED bootstrap on
the delta, both leave-one-out and best-subset-add; a redundancy matrix;
and an L2 logistic combiner under leave-cluster-group-out CV used only
as a measuring instrument. Everything is EXPLORATORY per the C4 sample-
size gate: the expert lane has 8 misgrounded responses.

It also carries the H7 half that was dropped. C3's gate was disjunctive
("checker-call reduction OR decision-quality gain") and Stage 7's frozen
falsifier list kept only the economic disjunct. Decision quality is
measured here on receipts where the lint was never in the loop, against
the checker verdict and against gold token-F1, stratified by the two
populations the lint was built for.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H9ToHYJVDxfeJcJwdzrP2H