ComputeVisibilityFromRoot(null, …) now returns null (outdoor root) instead of
calling FindCameraCell(fallbackPos). Retail CellManager::ChangePosition
(0x004559B0) reads the transition-owned curr_cell — it does NOT re-derive from
a static position. W2a guarantees CurrCell is set from the first tick, so the
AABB fallback is dead. Deleted: FindCameraCell (389–446), _lastCameraCell,
_cellSwitchGraceFrames, CellSwitchGraceFrameCount. GetVisibleCells retains a
brute-force AABB scan for test-compat; ComputeVisibility stays for the same
reason. Updated 3 null-root tests in CellVisibilityFromRootTests to assert the
new null-returns-null behavior.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
6a1fbbd44e