GHSA-7qx6-f23w-3w7f: Unauthenticated Open Redirect, Arbitrary HTTP Response Header Injection, Missing CSRF, and Invisible-Mode Bypass in goshs `/?redirect` endpoint

The GET /?redirect endpoint in goshs v2.0.0-beta.6 performs an HTTP redirect to any attacker-supplied url= value and writes any attacker-supplied header=Name: Value pair into the response, without scheme/host validation, without a header-name allow-list, without authentication in the default deployment, and without the checkCSRF() guard that GHSA-jrq5-hg6x-j6g3 added to the other state-changing GET routes (?mkdir, ?delete). The same dispatcher also lacks an fs.Invisible branch, so the endpoint stays responsive in -I stealth mode and reliably fingerprints an “invisible” goshs deployment with a single request.