feat(migration): Phase 4-quater — relocate core/corpus.py vers evaluation/

feat(migration): Phase 4-ter — relocalisation Cercle 1 → Cercle 2

fix(security,metrics): Sprint A14-S1 — boucher les 6 P0 du rewrite ciblé

refactor(measurements): split runner.py (1019 → 6 sub-modules) by concern