DirectorySlash Off

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    
    # Serve static files from /app outside document root
    RewriteRule ^app/(.*)$ /app-proxy.php?file=$1 [L,QSA]
    
    # Don't rewrite if file exists
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_URI} !^/app/
    RewriteRule ^(.*)$ /index.php [L,QSA]
</IfModule>