Live retail cdb trace (tools/cdb/cellar-corner-escape.cdb) of the Holtburg
cottage cellar-top corner decodes the ground truth: retail escapes by
step_sphere_up->step_up (196x vs 38 near-misses), transitioning the contact
plane from the ramp (N.z=0.78) onto the flat cottage floor (N.z=1.0, 76
landings). acdream slides at the lip and never makes that ramp->floor
transition -> the intermittent cellar wedge.
So the remaining cellar bug is the #98-core step-up-onto-cottage-floor
(DoStepDown / step_sphere_down / find_walkable), which the shipped B1 (abbd761)
+ slide_sphere (0935a31) fixes got close to but didn't finish. Door still
blocks; generic step-up climbs; cellar went always-stuck -> works-mostly.
Next (handoff doc): instrument acdream's OWN corner path (does step_up fire at
the lip and fail to land on the cottage floor?) before porting the lip-climb --
no guessing (#98 saga rule).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
