backport: bitcoin#28170, bitcoin#29524, bitcoin#28464, bitcoin#28578, bitcoin#28832, bitcoin#28075 - #7940

On December 2, 2026, GitHub will restrict `pull_request_target` on public repositories by default. To continue allowing the event trigger, configure an Actions policy. Learn more: https://gh.io/securely-using-pull_request_target#default-policy-for-pull_request_target