The camera spring-arm sweep already resolves the collided eye's cell (ResolveResult.CellId
= sp.CurCellId = retail viewer_cell = sphere_path.curr_cell, update_viewer pc:92871).
Return it from SweepEye so the render can root on the viewer cell (Phase W single-viewpoint
V1, Task 1). Pure plumbing — behavior unchanged; callers extract .Eye. 174 App tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
