feat: add Input, Separator, Sheet, and Sidebar components

- Implemented Input component for user input fields.
- Created Separator component for visual separation in UI.
- Added Sheet component for modal-like overlays with customizable content.
- Developed Sidebar component with collapsible functionality and mobile responsiveness.
- Introduced Skeleton component for loading placeholders.
- Implemented Tooltip component for contextual hints.
- Updated global CSS variables for sidebar theming.
- Added useIsMobile hook for responsive design handling.
- Modified projects route to include ProjectSidebar.
- Enhanced Tailwind CSS configuration for improved styling.
- Updated Vite preload configuration for custom entry file naming.

src/renderer/components/ui/skeleton.tsx

@@ -0,0 +1,15 @@
+import { cn } from "@/lib/utils"
+
+function Skeleton({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) {
+  return (
+    <div
+      className={cn("animate-pulse rounded-md bg-primary/10", className)}
+      {...props}
+    />
+  )
+}
+
+export { Skeleton }