feat: add floating scroll-to-top button

src/App.css

@@ -2689,3 +2689,55 @@ body[data-theme='light'] .console-separator::after {
   background: #3b82f6 !important; /* Standout blue badge for activities */
 }
 
+/* Scroll To Top Button */
+
+.scroll-to-top {
+  position: fixed;
+  bottom: 24px;
+  right: 24px;
+
+  width: 52px;
+  height: 52px;
+
+  border: none;
+  border-radius: 50%;
+
+  background: var(--aside-bg);
+  color: var(--text-color);
+
+  cursor: pointer;
+
+  display: flex;
+  align-items: center;
+  justify-content: center;
+
+  box-shadow: 0 4px 12px var(--box-shadow);
+
+  z-index: 999;
+
+  transition:
+    transform 0.2s ease,
+    background 0.2s ease,
+    color 0.2s ease;
+}
+
+.scroll-to-top:hover {
+  transform: translateY(-3px);
+  background: #4aed88;
+  color: #1c1e29;
+}
+
+.scroll-to-top:active {
+  transform: scale(0.95);
+}
+
+/* Mobile */
+
+@media (max-width: 768px) {
+  .scroll-to-top {
+    width: 46px;
+    height: 46px;
+    bottom: 18px;
+    right: 18px;
+  }
+}

src/App.js

@@ -7,6 +7,7 @@ import NotFound from './pages/NotFound';
 import {Toaster} from "react-hot-toast";
 import LandingPage from './pages/LandingPage';
 import ErrorBoundary from './components/ErrorBoundary';
+import ScrollToTopButton from "./components/ScrollToTopButton";
 
 function App() {
   return (
@@ -33,6 +34,7 @@ function App() {
           <Route path='/editor/:roomId' element={<EditorPage />}></Route>
           <Route path='*' element={<NotFound/>}></Route>
         </Routes>
+        <ScrollToTopButton />
       </BrowserRouter>
     </ErrorBoundary>
   );

src/components/ScrollToTopButton.jsx

@@ -0,0 +1,38 @@
+import { useEffect, useState } from "react";
+import { ChevronUp } from "lucide-react";
+
+function ScrollToTop() {
+  const [visible, setVisible] = useState(false);
+
+  useEffect(() => {
+    const toggleVisibility = () => {
+      setVisible(window.scrollY > 300);
+    };
+
+    window.addEventListener("scroll", toggleVisibility);
+
+    return () =>
+      window.removeEventListener("scroll", toggleVisibility);
+  }, []);
+
+  const scrollToTop = () => {
+    window.scrollTo({
+      top: 0,
+      behavior: "smooth",
+    });
+  };
+
+  if (!visible) return null;
+
+  return (
+    <button
+      className="scroll-to-top"
+      onClick={scrollToTop}
+      aria-label="Scroll to top"
+    >
+      <ChevronUp size={22} />
+    </button>
+  );
+}
+
+export default ScrollToTop;