Replace simplified push-out with retail-faithful SlideSphere and
AdjustOffset from transition_pseudocode.md. Crease-projection between
collision normal and contact plane produces smooth wall-sliding.
Object collision uses proper rotation transform to object-local space.
SlideSphere (section 6): computes crease direction via cross product
of collision normal and contact plane normal, projects displacement
onto the crease, then applies the correction offset. Handles three
cases: crease exists, parallel same-direction, parallel opposing.
AdjustOffset (section 6): adds safety check to keep sphere above
contact plane by computing signed distance and pushing up along Z
when the sphere dips below.
FindObjCollisions: removes ad-hoc penetration push-out, now calls
SlideSphere after BSP hit detection for proper wall-slide behavior.
Also fixes: ShadowEntry gains Rotation field, tests updated to match
Register signature, unused variables removed from GameWindow.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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