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/routes/projects.tsx

@@ -1,4 +1,5 @@
 import { createFileRoute } from '@tanstack/react-router';
+import { ProjectSidebar } from '@/components/projects/ProjectSidebar';
 
 export const Route = createFileRoute('/projects')({
   component: ProjectsPage,
@@ -6,8 +7,11 @@ export const Route = createFileRoute('/projects')({
 
 function ProjectsPage() {
   return (
-    <div className="flex items-center justify-center h-full text-muted-foreground text-sm">
-      Projects — coming in US-006
+    <div className="flex h-full overflow-hidden">
+      <ProjectSidebar />
+      <div className="flex-1 flex items-center justify-center text-sm text-muted-foreground">
+        Select a project to view details
+      </div>
     </div>
   );
 }