Serve static JS-App from directory in Laravel for authorized users

I have a Js app. It has its own directory and everything it needs is in that directory. I want to use this app in Laravel project now. But it should only be available for logged in users. Now I do not know how to do it. I would use cookie-authentication, but how should it work? If JS app is in public directory it is always open for access and has no access to csrf token. If it is in resourses I can only provide single files in view. How can I make a whole directory available? At the moment I see only one possibility:

web.php

Route::middleware(['auth:sanctum', 'verified'])->get('/jsapp', function () {
    return view("jsapp");
})->name('jsapp');

Route::middleware(['auth:sanctum', 'verified'])->get('/jsapp/{path?}', function (Request $req, $path) {
    return serve_file_somehow("path_to_project_root", $path);
});

This Js-App polls the server regularly to check if the user is still logged in.My question how to implement this serve_file_somehow feature? Or maybe there are other solutions for this situation? Is there any kind of .htaccess -magic that can be implemented?

Js-App directory structure:

resources/views/jsapp
-- index.html
    <html>
        <link href="css/styles.css" />
        <script src="js/index.js />
    </html>
-- css/styles.css
-- js/index.js
-- images/img1.jpg

What bothers me is that you reimplement the functions of a web server via PHP/Laravel.

Solution

You should serve the index.html file contents through a blade template index.blade.php

<html>
  <meta name="csrf-token" content="{{ csrf_token() }}">
  <link href="/css/styles.css" />
  <script src="/js/index.js />
</html>

with a protected route:

Route::middleware(['auth:sanctum', 'verified'])->get('/jsapp', function () {
    return view("jsapp.index");
})->name('jsapp');

and put all javascript and css files in the public directory.