perf: speed up desktop startup and unify theme-aware branding (#596)

* fix: unify startup logo and loading theme behavior

Show desktop window immediately with animated splash logo
Align splash/logo colors with selected app theme and default themes
Keep auth loading state on full-screen logo without size jump
Make project SVG icons follow active app theme
Use the active theme foreground color for project icons discovered from favicons
Apply server-side SVG color overrides for currentColor icons via icon request params
Keep non-SVG project icons unchanged while preserving existing fallback behavior

* perf: speed up desktop startup and unify loading logo visuals

Desktop startup now shows UI sooner while backend boot continues in background
Startup host probing uses a faster local path with safer remote fallback retries
OpenChamber logo cube highlights now match splash screens consistently

* fix: keep macOS traffic-light buttons in the correct position on load

Stop native window title updates on macOS during app initialization
Prevent title bar relayout that reset custom traffic-light positioning

* fix: recover missing providers and agents after fast startup

Retries provider/agent loading when connection is up but core config is still empty
Prevents cold-start state where models/agents appear only after manual project switch
Keeps startup responsive with throttled background recovery in app bootstrap

packages/ui/src/lib/desktop.ts

@@ -41,6 +41,10 @@ export type DesktopSettings = {
   themeVariant?: 'light' | 'dark';
   lightThemeId?: string;
   darkThemeId?: string;
+  splashBgLight?: string;
+  splashFgLight?: string;
+  splashBgDark?: string;
+  splashFgDark?: string;
   lastDirectory?: string;
   homeDirectory?: string;
   // Optional absolute path to `opencode` binary.