Aggressively deprecate app.urls.xyz & update docs to avoid it

Closes #1587

examples/middleware/src/middleware.tsx

@@ -9,7 +9,7 @@ export async function middleware(request: NextRequest) {
   const user = await hexclaveServerApp.getUser();
   if (!user) {
     console.log('User in middleware is not logged in. Redirecting to sign-in page');
-    return NextResponse.redirect(hexclaveServerApp.urls.signIn);
+    return NextResponse.redirect(new URL('/handler/sign-in', request.url));
   }
 
   console.log('User in middleware is logged in. ID: ', user.id);