experiment 2

DSH 插件：同一任务、同一代码基线，多 Variant（模型/Preset）并行对照实验、EvidenceReceipt 对比与胜出 Patch 导出

DSH Agent experiment & A/B comparison — run the same coding task in two isolated workspaces and compare objective metrics (wall time, turns, tokens, diff, evaluator results).