Freezes the pond API for D (broom) and A (HUD), resolves D's tn-1.04
cliff as real ponding load rather than solver instability, and flags that
flat rigs die to wind before water on the current yard — so ponding is a
twist-tax today unless the yard gets a non-collinear level anchor trio.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>