Fix URL parameter logic - now both ESV and NKJV show version parameters consistently

Previously only NKJV added ?version=nkjv to URL while ESV had no parameter (treated as 'default')
Now both versions properly display in URL: ?version=esv and ?version=nkjv
This ensures consistent URL handling and bookmarking for all Bible versions

frontend/src/App.tsx

@@ -58,7 +58,7 @@ function App() {
     loadBooks();
     // Update URL with version when it changes
     const url = new URL(window.location.href);
-    if (selectedVersion !== 'esv') { // Only add if not default
+    if (selectedVersion) { // Add version parameter when selected
       url.searchParams.set('version', selectedVersion);
     } else {
       url.searchParams.delete('version');