foundations: design tokens (light + dark) and CSS reset

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.tsx

@@ -1,5 +1,3 @@
-function App() {
-  return <div>Cameleer3</div>
+export default function App() {
+  return <div>Cameleer3 Design System</div>
 }
-
-export default App