build: full patchset from cms-externals; docs: improve description

[lgray]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

This applies cms thread-safety/c++ modernization patches to fastjet-contrib and enables a future windows build.

Add some strictness to package_contents checks.

c.f. https://github.com/cms-externals/fastjet-contrib/tree/cms/v1.101 and cms-externals/fastjet-contrib#19

Fixes #13

[lgray]

@conda-forge-admin, please rerender

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/recipe.yaml) and found it was in an excellent condition.

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-webservice.

I tried to rerender for you, but it looks like there was nothing to do.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/15611867131. Examine the logs at this URL for more detail.}

[lgray]

@matthewfeickert Just some final cruft clean up and dealing with chores. Also prepares this feedstock for the eventuality of windows builds. Review and merge at your leisure.

[lgray]

ok - added some strictness to the package content checks to make sure we're always producing cmake info from now on.

[matthewfeickert]

@conda-forge-admin, please rerender