[Justin Chung (jshigetomi)]

PR Summary

This is the TFM-only extraction from #1963 after the combined RID/TFM implementation was reverted by #2070. It adds -TargetFramework and automatic host-framework selection to Install-PSResource without restoring any RID filtering, RuntimeIdentifier helpers, or -RuntimeIdentifier surface.

Library filtering now operates per relative asset path rather than choosing one entire lib/{tfm} directory. When the same asset exists under multiple compatible target frameworks, NuGet's framework reducer selects the nearest compatible variant for the current or explicitly requested target. Unique compatible assets remain installed even when they are spread across multiple TFM folders. This preserves the Az.Accounts shape called out in #2070 (lib/net45, lib/net47, and lib/netstandard2.0) while still removing redundant variants.

An explicit -TargetFramework can also add assets to an already-installed copy of the same version. Merge state is scoped to each parent install work item, and the merge only adds missing files without overwriting existing content. -Reinstall retains full replacement behavior.

TFM-specific dependency-group refinement is intentionally deferred in this draft. Dependency parsing remains unchanged, so an explicit target does not silently cause dependency groups to be selected using the current host framework. The empty dependencyGroups behavior fixed after the revert is not reintroduced.

Validation:

• Passed: pwsh -NoLogo -NoProfile -File .\build.ps1 -Build with .NET SDK 10.0.402 on PATH.
• Passed: direct dotnet publish .\src\code\Microsoft.PowerShell.PSResourceGet.csproj --configuration Debug --framework net472 --no-restore --verbosity minimal.
• Passed on PowerShell 7.6.9: Invoke-Pester -Script .\test\InstallPSResourceTests\InstallPSResourceTargetFramework.Tests.ps1 (8 passed, 0 failed).
• Passed on Windows PowerShell 5.1: Invoke-Pester -Script .\test\InstallPSResourceTests\InstallPSResourceTargetFramework.Tests.ps1 (8 passed, 0 failed).
• Passed: Invoke-ScriptAnalyzer -Path .\test\InstallPSResourceTests\InstallPSResourceTargetFramework.Tests.ps1 -Severity Warning,Error (0 findings).

PR Context

The original platform-aware install work combined RID and TFM behavior. This standalone draft limits the change to TFM-aware lib/ asset selection and adds a regression fixture shaped like the Az.Accounts package layout that caused #1963 to be reverted. RID filtering is being handled separately.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: or [ WIP ] to the beginning of the title (the WIP bot will keep its status check at Pending while the prefix is present) and remove the prefix when the PR is ready.
• Breaking changes
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  • Documentation needed
    • Issue filed:
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed: Documentation Request: Platform-Aware Installation for Install-PSResource MicrosoftDocs/PowerShell-Docs-PSGet#347
• Testing - New and feature
  • N/A or can only be tested interactively
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  • Make sure you've added a new test if existing tests do not effectively test the code changed
• Tooling
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