Multi-shape entity registration matching retail's CPhysicsObj model: one
logical entity emits N ShadowEntry rows (one per CylSphere / Sphere /
Part-BSP), all sharing the entity's EntityId. _entityShapes caches the
original shape list per entity for UpdatePosition to recompose part
transforms when the entity moves.
Existing UpdatePhysicsState / Deregister / GetObjectsInCell /
AllEntriesForDebug work unchanged — they iterate by EntityId; multiple
matching entries get handled automatically.
AllEntriesForDebug updated to enumerate all parts per entity (not just
the first) by iterating the first cell that holds entries for each entity.
Single-shape callers that previously relied on deduplicated-by-EntityId
behavior are unaffected since they register exactly one entry per entity.
Six new tests: AllShareEntityId, EmptyShapeList_NoOp,
Deregister_RemovesAllParts, UpdatePhysicsState_PropagatesEtherealToAllParts,
PartsAcrossMultipleCells_AllCellsListed, Register_SingleShapeCompat_Unchanged.
All 24 existing ShadowObjectRegistry tests pass via the unchanged
single-shape Register API. 11/11 CellarUpTrajectoryReplayTests pass.
7/7 ShadowShapeBuilderTests pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
