Macos 26 runner

[Dave Allured - NOAA Affiliate via macports-dev]

Github says that a beta version of a macOS 26 runner is available.  Can
this be activated for MacPorts CI?  Can  build failures on the OS 26 runner
be temporarily ignored for merging port updates?
https://github.blog/changelog/2025-09-11-actions-macos-26-image-now-in-public-preview/