macOS 15 Actions runner: UDP/mDNS networking failure

[b00f]

Description

We’re encountering issues with UDP and mDNS networking on the latest macOS 15 GitHub Actions runners. Workflows that previously worked on macOS 14 now fail, apparently due to missing “local network access” permissions.
UDP traffic and mDNS service discovery do not work as expected. This is reported here, which describes multicast socket routing errors on macOS 15.