Reverted a redundant widening of the main MC gate (typical ranges) after confirming
test_gate_mc_extreme_multipliers already bit-identity-tests boost in [1,5], beta in
{0,0.2,0.8,1}, mc in {0,0.5,1}, and the OB agreement boundary (N=200k, exact !=).
Added a cross-reference note. All 6 gates green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>