Include Pkcs (net10.0 & -windows) in aspnetcore transport pack

[ViktorHofer]

Fixes #117146

[Copilot]

Pull Request Overview

This PR ensures the System.Security.Cryptography.Pkcs assembly for the net10.0-windows TFM is included in the ASP.NET Core transport pack.

• Adds System.Security.Cryptography.Pkcs to the shared framework props so it’s available in .NET 10.
• References the Pkcs project with a windows-specific TFM and wires it into the transport pack MSBuild logic.
• Adjusts path separators in packaging.targets to flatten package and symbol output paths.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/libraries/NetCoreAppLibrary.props	Added System.Security.Cryptography.Pkcs to the list of included shared framework assemblies
src/libraries/Microsoft.Internal.Runtime.AspNetCore.Transport/src/Microsoft.Internal.Runtime.AspNetCore.Transport.proj	Added a windows-targeted Pkcs ProjectReference and a custom target to surface it
eng/packaging.targets	Switched to forward slashes and removed redundant separators in package/symbol paths

Comments suppressed due to low confidence (3)

src/libraries/Microsoft.Internal.Runtime.AspNetCore.Transport/src/Microsoft.Internal.Runtime.AspNetCore.Transport.proj:40

• Consider adding an integration or packaging test to verify that the Pkcs DLL and its PDB actually end up in the runtimes/win/lib/$(NetCoreAppCurrent) folder of the generated ASP.NET Core transport package.

    <ProjectReference Include="$(LibrariesProjectRoot)System.Security.Cryptography.Pkcs\src\System.Security.Cryptography.Pkcs.csproj"

eng/packaging.targets:253

• Mixing forward slashes and backslashes in MSBuild paths can lead to inconsistent output on Windows. Consider using $(BuildOutputTargetFolder)\$(_referringTargetFramework)\ or normalizing separators uniformly.

                              PackagePath="$([MSBuild]::ValueOrDefault('%(ReferenceCopyLocalPaths.PackagePath)', '$(BuildOutputTargetFolder)/$(_referringTargetFramework)/'))" />

eng/packaging.targets:255

• This relies on PackagePath ending with a slash. If it doesn't, output paths may run together. You might add a slash in the metadata or use TrimEnd('\/') and then append a single separator.

                                   TargetPath="/%(TfmSpecificPackageFile.PackagePath)%(Filename)%(Extension)"

[wtgodbe]

LGTM

[ViktorHofer]

/ba-g failures are unrelated