Final form pinned per product decision: one product and one codebase (nebula.exe / nebula_app) with GPUI as its in-process UI layer; nebula_gpui is a validation lab whose proven modules get integrated into nebula_app, never a second product. Grid rendering stays first-party via the render contract; powerline/fastfetch/CJK fidelity are acceptance gates. Mega-file split (display/mod.rs 10k+ lines etc.) is scheduled as a dedicated refactor pass after GPUI integration.