Root cause of the eigen-ON 3x slow pose convergence (probed synthetically):
pedestal-included covariance inflates the peak eigen lambdas; sqrt(lambda)
reaches imp.eig_max_sqrt (6) where setEigenTransform's k=max(0,1/sqrt(l)-1/6)
ZEROES the tile's measurement components - blur-wide tiles (sigma ~2.5-3 px,
the lean consolidated-average x center regime) contribute nothing and the
solve limps on the few sharp tiles. Companion zero-build retune: raise
imp.eig_max_sqrt 6 -> ~20 (dialog) when re-enabling eigen. Solver algebra
verified consistent (jt, both Y-Fx variants, WJtJ share the transform).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>