Revert HEAD to submitted tier-5 model (9e196608); htop90=7 cell remains in history at 6e7450f0

tiers 5-7 recurrent reduction cell (htop90=7)

tier5 route [2^32,2^64) to base-16 modmul decoder (htop90=5)

tier-3 modmul scratchpad: htop90=3 (tier1 1.0, tier2 1.0, tier3 0.99)