A WellStrength that evaluates negative, NaN or infinite now throws at construction (it built an
antimass well with NaN height). New tests: the core-inside-Roche guard judged at every mass on
curves that cross in the generated range; per-body multipliers move neither strength, core nor
Roche limit; potential and force consistency inside the cores' outer bands (0.5 R to R); a
moving Ship feels the field where it has moved to.
Not built or run locally; verified in the Yggdrasil job.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>