Arbor — Autonomous Optimization via Hypothesis Tree Refinement Overview This skill runs an Autonomous Optimization (AO) loop: starting from an existing artifact and a measurable objective, improve it through many rounds of experiment and evaluation — without step-by-step human supervision, while checking for overfitting to the development signal. It's the right tool when the bottleneck isn't writing one good change, but organizing dozens of trials so that lessons accumulate instead of evaporating. It implements Hypothesis Tree Refinement (HTR) from Arbor (Jin et al., 2026). The key idea: keep…