Working ECEF to ENU (Rotate Flat!)

Refactor rotate-flat baking with robust root handling. Replaces rotateFlatByPretransformingAndBaking with rotateStrictThenBakeRecursive, improving root node selection and mesh baking logic. Adds verbose diagnostic helpers, robust quaternion/scale handling, and stricter mesh sharing checks. Refactors math utilities and mesh baking to ensure geometry is rewritten in-place with correct transforms.

Author: ryanhlewis