Every response now carries:
X-Frame-Options: DENY
Content-Security-Policy: frame-ancestors 'none'
Prevents the WebUI from being embedded in a third-party iframe.
Combined with the existing CSRF Origin-host check, this closes the
last meaningful UI-redress surface.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
