impr(nav): avoid duplicate browser history entries when re-clicking same nav button (@byseif21) (monkeytypegame#6624)

### Description

Closes monkeytypegame#6623

Author: byseif21

frontend/src/ts/controllers/route-controller.ts

@@ -159,7 +159,18 @@ export function navigate(
   }
   url = url.replace(/\/$/, "");
   if (url === "") url = "/";
-  history.pushState(null, "", url);
+
+  // only push to history if we're navigating to a different URL
+  const currentUrl = new URL(window.location.href);
+  const targetUrl = new URL(url, window.location.origin);
+
+  if (
+    currentUrl.pathname + currentUrl.search + currentUrl.hash !==
+    targetUrl.pathname + targetUrl.search + targetUrl.hash
+  ) {
+    history.pushState(null, "", url);
+  }
+
   void router(options);
 }