CVE-2026-67435: linuxfabrik-lib: fetch() forwards credential headers across a cross-origin redirect

lib.url.fetch() follows HTTP redirects (follow_redirects=True). httpx strips only Authorization and Cookie when a redirect crosses the origin, so any other caller-supplied credential header (a session token such as Redfish’s X-Auth-Token, an API key, …) was still sent to the redirect target. A malicious or redirect-capable server can therefore answer an authenticated request with a 3xx to an attacker-chosen host and receive the credential (server-side request forgery + token disclosure). The pre-httpx urllib implementation was worse: it forwarded every header, including Authorization, across cross-host redirects.