Adds separately scoped two-cache MSI coherence and SRAM BIST verification collateral while preserving the baseline cache closure. Evidence includes 16/16 directed MSI checks, 25/25 C++-modeled randomized MSI workloads, 3/3 MSI mutation detections, 7/7 standalone March C-minus BIST checks, and 2/2 integrated parity/SECDED cache-array BIST variants. The full release gate remains green, including 22/22 directed tests, 127/127 trace replays, 55/55 interaction crosses, 100/100 stress rows, 4/4 baseline mutations, and 7/7 SECDED RAS coverage.