fix: fix 404 fallback

Author: Mister-Hope

packages/client/src/router/resolveRoute.ts

@@ -28,7 +28,7 @@ export const resolveRoute = <T extends RouteMeta = RouteMeta>(
   // the route not found
   if (!routes.value[routeKey]) {
     return {
-      ...routes.value['/404.html'],
+      ...routes.value['/404'],
       path: routeFullPath,
       notFound: true,
     } as ResolvedRoute<T>