V6a: pass the stable devices array to resolvedLightSources — the WeakMap
cache is keyed by array identity, a spread guaranteed a miss on every
render in BOTH cards (full-card regression since beta.4).
V6b: the static wall geometry now carries the same non-enumerable
sourceFingerprint tag the full card attaches, so buildLightBarrierScene
takes the fast recutWallBodiesGeometry path on door state changes.
V6c: the static barrier-scene cache is an LRU of 8 per space (parity
with _lightBarrierPool) — a flipping door reuses both of its scenes.
V6d: enabledClip is cached by geometry fingerprint + disabled-room set,
with the full card's bbox prefilter for decor bodies.
User-Visible: yes
Issue: #375
