refactor: replace x-frame-options with CSP frame-ancestors

Signed-off-by: rare-magma <[email protected]>

public/_headers

@@ -1,8 +1,7 @@
 /*
-  X-Frame-Options: DENY
   Referrer-Policy: no-referrer
   Permissions-Policy: accelerometer=(), autoplay=(self), camera=(), display-capture=(self), fullscreen=(self), geolocation=(self), gyroscope=(self), magnetometer=(self), microphone=(), payment=(), picture-in-picture=(self), sync-xhr=(), usb=()
-  Content-Security-Policy: default-src 'self'; img-src https://guitos.app https://www.w3.org data:;
+  Content-Security-Policy: default-src 'self'; img-src https://guitos.app https://www.w3.org data:; frame-ancestors 'none';
 
 https://guitos.pages.dev/*
   X-Robots-Tag: noindex