Benchmark Qwen3.6-35B-A3B G2 — 3-way reward ablation

[caiovicentino]

The 35B-A3B SAE at L23 has G1 ρ=0.522 (validated). Next: run Stage Gate 2 three-way reward ablation (R0 / R1 / R2). Likely requires A100; document cost + runtime.