Add native macOS vibrancy behind the left sidebar (the only translucent
surface; header/chat/right sidebar stay opaque), plus a setting to turn it off.
- Window created with vibrancy applied after first show (avoids the cold-launch
no-composite quirk); minimize/restore suppress the frost during the genie
animation. Renderer frosts the sidebar via --sidebar-vibrancy-overlay once
data-oc-vibrancy[-ready] are set; project-actions pill matches when open.
- data-oc-vibrancy-ready defaults are set in cssGenerator (DOM guaranteed),
not the preload (document-start race left the sidebar un-frosted on launch).
- prefers-reduced-transparency falls back to solid surfaces.
- Appearance settings (macOS desktop only): a checkbox to enable/disable
vibrancy, persisted to settings.json and applied via a Save & restart button
(vibrancy is a window-creation option, so it needs a relaunch).
Bohdan Triapitsyn
3541bc63f9