Twin 3D scene is visually modest, not cinematic – single light, no post-processing, fixed camera

DECIDED 2026-09-06: Twin 3D scene RETIRED, not polished. Lands in PR #197 (feat/zigbee-completion-automation-v2, commit 7bb203f). Evidence: both host routes (/live/twin, /ops/dash) redirect to Overview so DscTwinCanvas always returned null; tracker already rated it ‘no unique data, ignores shared component library’; AGENTS.md bans blank WebGL theater. Worse than ‘unmounted’: TwinKeepAlive was mounted in App on EVERY page and lazy-imported the R3F/three chunk for a component that never rendered. Removed the App mount, deleted the four Twin files, dropped the dead .dsc-twin-* CSS. three/@react-three deps stay (AirflowParticleScene uses them). LEGACY_REDIRECTS for /live/twin and /ops/dash kept for old bookmarks. Twin SF1000 lamp (light.dsc_hub_twin_sf1000) is unrelated and untouched. tsc –noEmit green. Revive path if ever wanted: git history (PR #182 R3F simplification). — ORIGINAL: Twin 3D scene visually modest — single light, no post-processing, fixed camera.