round5-B 2B: per-step CE (hard-easy steps +0.067 -> +0.433, CE -0.8) + serve_contract r5b-1

round7 2B: round7_2b_results.md

PonderNet x MiniCPM5-2B: modeling + train/eval/probe/RL, configs for round4-5, docs (round4 +0.498 hard-easy)