Brainstormed + approved 2026-05-21 for M1.5 milestone work. Designs
the cdb probe spike methodology (7 retail breakpoints + new
[push-back] probe) to capture retail's per-tick BSP collision
response state at 9 indoor scenarios (4 buildings + 5 dungeon sites)
and compare against acdream. Working hypothesis: BSPQuery.AdjustSphereToPlane
or its callers over-correct vs retail, producing the family of
indoor symptoms (walls walk through, ping-pong, vibration, multi-Z
falling) plus driving the existing #90 + TryFindIndoorWalkablePlane
workarounds. A6 ships in 4 slices: P1 probe spike, P2 analysis,
P3 surgical fixes, P4 workaround removal + acceptance.
Phase O (DatPath Unification) pre-empted M1.5 and shipped 2026-05-21;
A6 resumes from Phase O state. Phase O only touched rendering/dat
code; indoor physics design is unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>