Update app routing to use index.php instead of proxy

Remove app proxy rule and add condition to route /app requests to
index.php while preserving other existing behavior

content/.htaccess

@@ -3,12 +3,12 @@ DirectorySlash Off
 <IfModule mod_rewrite.c>
     RewriteEngine On
     RewriteBase /
-    
-    # Serve static files from /app outside document root
-    RewriteRule ^app/(.*)$ /app-proxy.php?file=$1 [L,QSA]
-    
+
+    # Route /app requests to index.php
+    RewriteCond %{REQUEST_URI} ^/app/
+    RewriteRule ^(.*)$ /index.php [L,QSA]
+
     # Don't rewrite if file exists
     RewriteCond %{REQUEST_FILENAME} !-f
-    RewriteCond %{REQUEST_URI} !^/app/
     RewriteRule ^(.*)$ /index.php [L,QSA]
 </IfModule>