nx_lbp_cluster.nx

nx_lbp_cluster.nx -- SOVEREIGN face-descriptor RUNG 4 GATE: greedy chi-square clustering of descriptors into person groups (cluster_greedy in nx_lbp_core.nx). Pure NishiLang, no benchmark. KAT on synthetic descriptors with 3 clearly-separated groups -> exactly 3 clusters with correct membership; plus threshold neg-controls (huge thresh -> 1 cluster, zero thresh -> every item its own). This is the engine that will turn the corpus descriptor store into galx_face_index (cid->person). Build/run: ./_offc/nx_sov_build_run.elf nx_lbp_cluster license_tier: ORIGINAL