All float-to-int conversions replaced with threshold comparisons:
- round_rne_u0_8: mantissa rounding via Float32 comparisons → Int32 constants
- abs_scaled_to_e2m1_idx: direct |scaled| → E2M1 index (no half_step needed)
- Verified 0/500 trial failures against Python reference
Key thresholds (RNE boundaries):
- 0.25, 0.75, 1.25, 1.75, 2.75, 3.75, 5.25 with > vs >= for RNE tie-breaking
- Fixed: 2.75 must use >= (not >) to match round(5.5)=6 RNE
biondizzle
dabcc415a8