fix: auto-reload on stale chunk load failure (vite:preloadError)

When a new deploy lands while a tab is open, lazy-loaded chunks (like
GifPicker) disappear because their content-hash filename changes. Vite
dispatches a vite:preloadError event in this case. We reload once and
clear the flag on successful load so future deploys can trigger again.

src/index.tsx

@@ -68,6 +68,16 @@ if ('serviceWorker' in navigator) {
   });
 }
 
+// Reload once if a lazy-loaded chunk is missing (stale deployment)
+window.addEventListener("vite:preloadError", () => {
+  if (!sessionStorage.getItem("chunk-reload-attempted")) {
+    sessionStorage.setItem("chunk-reload-attempted", "1");
+    window.location.reload();
+  }
+});
+// Clear the reload flag after a successful load so future deploys can still trigger a reload
+window.addEventListener("load", () => sessionStorage.removeItem("chunk-reload-attempted"));
+
 const mountApp = () => {
   const rootContainer = document.getElementById('root');