Merge branch 'mc/http-emptyauth-negotiate-fix'

The 'http.emptyAuth=auto' configuration now correctly attempts Negotiate authentication before falling back to manual credentials. This allows seamless Kerberos ticket-based authentication without requiring users to explicitly set 'http.emptyAuth=true'. * mc/http-emptyauth-negotiate-fix: doc: clarify http.emptyAuth values t5563: add tests for http.emptyAuth with Negotiate http: attempt Negotiate auth in http.emptyAuth=auto mode http: extract http_reauth_prepare() from retry paths