GHSA-jmc6-2wr8-h3wj: Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin

## Summary Any authenticated user with access to a shared terminal server could get script of their choosing to run in the Open WebUI origin itself. The in-app port preview rendered the content of a previewed port in an iframe whose sandbox always granted `allow-same-origin` alongside `allow-scripts`, and that content is served from a path on the application's own origin, so the sandbox provided no isolation at all. Script served on a previewed port could read the victim's session token and take over the account. …