3.9.1 release tracking

[emillon]

• have a good fix for dune process hangs on macos #8083 (temporary list)
  • fix: disable background threads where we use fork #8100
  • fix: disable threaded console when we use fork #8121
  • fix: Initialize async IO thread lazily #8122
• backports
  • [3.9] backport #8100 #8127
  • [3.9] backport #8121 #8125
  • [3.9] backport #8122 #8126
• release [new release] dune (15 packages) (3.9.1) opam-repository#24073
• triage
• changelog merged chore: merge 3.9.1 changelog #8129
• discuss https://discuss.ocaml.org/t/ann-dune-3-9-0/12530/3
• ocaml.org Add changelog for dune 3.9.1 ocaml.org#1386

[tmcgilchrist]

thank you @emillon