feat(sprint-H.2.c-d)!: suppression complète de adapters/legacy_engines/ et adapters/legacy_pipelines/

chore(sprint-H.2.c.0): cleanup tests legacy + migration mocks → BaseOCRAdapter

feat(sprint-H.3)!: renommage reports_v2/ → reports/

feat(sprint-H.1)!: suppression cli/, llm/, extras/, fixtures.py

feat(migration): Phase 7.A.1+7.A.2 — engines/ vers adapters/legacy_engines/

feat(migration): Phase 7.A.1 — engines/base.py vers evaluation/engines/base.py

feat(migration): Phase 5.E — generator + comparison + snapshot + data + templates + i18n

test: réorganiser les 110 fichiers tests/test_*.py par cercle architectural