Lluis Eriksson (2026). Many-Body Filling Turns Soft Spectral Leakage into a Maintenance Floor: Exact Filled-SSH Sum Rules and an Interaction-Stable Obstruction. AIRR.SCIENCE, ARR-2026-6YFENMGGBY9PPBF1, v1. https://airr.science/papers/ARR-2026-6YFENMGGBY9PPBF1/versions/v1/ Archived manuscript; ARR-2026-6YFENMGGBY9PPBF1 v1. Not peer reviewed by AIRR. Historical import; not assessed by AIRR.