feat(formats): Sprint A14-S9 — formats/alto/, formats/pagexml/, migration normalization

feat(pipeline): Sprint A14-S8 — CorpusRunner backpressure + timeout réel + cancellation

feat(pipeline): Sprint A14-S6 — PipelineSpec déclaratif + validation + YAML round-trip

feat(architecture): Sprint A14-S3 — squelette nouvelle architecture + tests d'invariants

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

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

feat(measurements): câbler les 13 modules test-only — baseline → 0

fix(zero-debt): éliminer toute la dette technique actionnable identifiée

refactor(measurements): split statistics.py (1128 → 8 sub-modules) by family

fix(audit-2): 5 correctifs supplémentaires d'un 2e tour d'audit

fix(audit): 5 corrections suite à l'audit complet de mes derniers sprints

refactor(report): split generator.py (1063 → 431 lines) by concern

refactor(report): consolidate 27 render helpers into render_helpers.py

test(architecture): 4 invariants structurels contre la dérive silencieuse