Port retail CameraManager::UpdateCamera's convergence snap (0x00456fcd):
once the per-frame lerp step is below 0.0004 m AND the rotation within
0.000199999995, freeze the damped eye at an exact fixed point instead of
Vector3.Lerp's endless sub-mm asymptote. The drift was walking the 3rd-person
eye across the vestibule/room portal plane at rest, flipping the per-frame
viewer-cell resolve 0170<->0171 -> the indoor grey/texture flicker. The
collided-eye firewall (separate publishedEye local) is already present.
Adds ApplyConvergenceSnap static (TDD: 3 unit tests + 1 integration freeze
test) + SnapEpsilon/RotCloseEpsilon. App suite 183 -> 187, all green.
Plan: docs/superpowers/plans/2026-06-05-indoor-viewer-cell-flicker-fix.md
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>