feat: move projects to sidebar rail and speed up session switching (#506)

* feat: move projects from header tabs to left sidebar rail

* refactor: remove variant from git generation session context

* feat: implemented drandrop action for navrails

* refactor: improve sidebar drag-and-drop smoothness and remove floating overlay

* fix: prevent mobile nav rail touch from closing drawer and opening menu

* fix: hide header tabs on desktop

* fix: prevent session flicker when switching projects

* style: soften chat panel divider borders

* style: improve icon contrast across core navigation

* fix: stabilize session selection during project switching

* style: unify sidebar surfaces and transparent section layers

* style: remove UI shadows and keep only scroll shadow

* perf: speed up project switching with cached session loading

* perf: speed up Git changes view and background refresh

* perf: make session switching lighter and less aggressive

* perf: optimized sessions list loading while project switching

* perf: smooth chat rendering and reduce interaction spikes

* fix: restore reliable load older messages visibility

packages/ui/src/components/layout/RightSidebar.tsx

@@ -61,7 +61,7 @@ export const RightSidebar: React.FC<RightSidebarProps> = ({ isOpen, children })
   return (
     <aside
       className={cn(
-        'relative flex h-full overflow-hidden border-l border-border bg-sidebar',
+        'relative flex h-full overflow-hidden border-l border-border/40 bg-sidebar/50',
         isResizing ? 'transition-none' : 'transition-[width] duration-300 ease-in-out',
         !isOpen && 'border-l-0'
       )}