Final submission snapshot for Journal of Cheminformatics, including the pre-registered sensitivity addendum (protocol/sensitivity_addendum_v1.md).
- 5-split checkpoint-selection sensitivity under fixed-final / global-vs-global / endpoint-vs-endpoint / hybrid rules (corrected MTL training; validation selection attenuates but does not reverse the absolute contrast; protocol interaction positive under every rule)
- Chemical-entity identity collision audit (L1 standardized-parent key, L2 InChIKey upper bound); Level-1 filtering leaves Gamma = +0.083 unchanged
- Unit tests for exact-key isolation and L1 determinism
- Manuscript updated: checkpoint narrative, SI Table S4 + Figures S3-S4, SI S12 identity audit