refactor: rename pastel app to color and update all references

components/layout/AppSidebar.tsx

@@ -17,7 +17,7 @@ import { cn } from '@/lib/utils/cn';
 import Logo from '@/components/Logo';
 import { useSidebar } from './SidebarProvider';
 import { Button } from '@/components/ui/button';
-import { PastelIcon, UnitsIcon, FigletIcon, MediaIcon } from '@/components/AppIcons';
+import { ColorIcon, UnitsIcon, FigletIcon, MediaIcon } from '@/components/AppIcons';
 
 interface NavItem {
   title: string;
@@ -46,9 +46,9 @@ const navigation: NavGroup[] = [
         icon: <FigletIcon className="h-4 w-4" /> 
       },
       { 
-        title: 'Pastel', 
-        href: '/pastel', 
-        icon: <PastelIcon className="h-4 w-4" />
+        title: 'Color Manipulation', 
+        href: '/color', 
+        icon: <ColorIcon className="h-4 w-4" />
       },
       { 
         title: 'Media Converter',