Merge topic 'gcc-import-std'

2a0ca6a26d ci: add jobs to test GCC 15-to-be with `import std`
469175c2e6 Experimental: recycle the `import std` UUID
a980dab9b1 gcc: support `import std`
2791b7564b Tests/RunCMake: handle C++26 support where needed

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !10023