New mutator that overwrites cached PhysicsState bits on every shadow copy
of the named entity. The existing CollisionExemption.ShouldSkip(...) check
(acclient_2013_pseudo_c.txt:276782) reads the same cached field, so a
post-spawn ETHEREAL flip is now honored on the next resolver tick without
any resolver-path change.
Retail anchor: CPhysicsObj::set_state at acclient_2013_pseudo_c.txt:283044.
Slice 1 scopes to the bare state-write — retail's cosmetic side-effect
handlers (0x800 lighting, 0x20 nodraw, 0x4000 hidden) don't fire for the
ETHEREAL bit and stay deferred.
Three TDD tests cover: ETHEREAL flip from 0->0x4; unregistered-entity
no-op; entity spanning multiple cells gets all copies updated.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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