Attached cdb to live retail (PDB MATCH), broke on PView::DrawCells (0x005a4840),
dumped cell_draw_num + cell_draw_list cell ids + the eye
(Render::FrameCurrent->viewer.viewpoint) while descending the Facility Hub spiral.
Retail's flood is dynamic and IDENTICAL in character to ours: from the spiral cells
it swings num 3->27 with gaze and collapses to 3 cells at many poses (cam=015d ->
{015d 015e 015f}). Our flood does the same (3->43). So retail does NOT keep the
staircase where we drop it -- the flood is exonerated as the cause.
Session trail (all in ISSUES #177): ruled out lighting, membership, camera coherence,
the collision sweep, the 0178/0182/0183 handoff cells, and edge-on eye-in-opening
(fix#1 shipped -> visual-gate-failed -> reverted, PortalVisibilityBuilder + AP-86 both
restored exactly). Freshest un-chased lead: the steps are STATIC objects (GfxObj
0x010000DE x6/cell) drawn via the viewcone cull, not cell shell.
Adds: Issue177StairDescentCameraFloodTests (real-camera+flood + composition +
flood-depth characterization pins) and a reusable retail-cdb capture toolchain
(tools/cdb/pview-verify.cdb, pview-spiral2.cdb with the correct top-level-qd detach --
qd in a CONDITIONAL bp action does NOT fire and strands cdb attached).
No production code change (fix#1 reverted). PARKED per user; M1.5 critical path next.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>