Measurement-only branch. Re-runs parse_and_solve on all 50 GSM8K train-sample
cases against the current parser (post-S.1/S.2) and produces a barrier-shift
ledger comparing v1 taxonomy to current behavior.
Results: admitted=3/50 (0014, 0018, 0042), wrong=0, barrier_shifted=27/50.
Context-filler dominance collapsed from 23→3 cases; compound_statement (6)
and novel_initial_form (5) are now the largest buckets.
Subsumption directive pinned: ADR-0137 SHALL re-derive all short-circuit
admissions as (DeferredCandidate, evidence, BindingProof) triples.
