v1.6.1

Fixed

• The apt-sources preflight check no longer hard-blocks an install on a
  transient mirror-probe timeout. The mirror-root HEAD probe was a single
  6-second shot that also followed redirects, so on a fresh node whose
  networking was still converging (or whose mirror root 301s to a host apt
  never contacts, like security.ubuntu.com to www.ubuntu.com) it could time
  out and abort the install even though apt itself was healthy. The probe now
  treats any HTTP response (including a redirect, without following it) as
  proof of reachability and no longer blocks on its own: the real
  apt-get update (now run under its own generous 75s budget instead of the
  generic 8s exec cap) is the decider. Genuinely broken apt egress still
  blocks, now with accurate attribution listing the unreachable mirrors, and
  a probe blip that apt survives is logged as transient and the install
  proceeds.