PR Summary

Fixes six confirmed defects found while triaging the PowerShell 7.7.0-rc.1 release-automation test failures:

• fail the startup assembly test only for unexpected additions, while retaining diagnostics for missing historical assemblies
• bound and clean up timed-out external clipboard helpers before reading process state
• preserve ModulePath setup errors and normalize logical paths without requiring them to exist
• retain job state, import errors, verbose output, paths, and hashes for executable-manifest tests
• make remote-session creation terminate and prevent null-session setup cascades
• calculate the expected MSIX PATH from package identity, including loose MSIX registration

The unconfirmed macOS SSH exception-mapping failure is intentionally unchanged pending reproducible SSH/DNS evidence.

PR Context

The 7.7.0-rc.1 release-automation comparison reported 19 new failures. Several were false failures or setup/diagnostic defects that prevented the tests from validating product behavior. The clipboard failure also exposed a product bug where Process.ExitCode was read after a timed wait returned false.

Validation:

• Import-Module .\tools\ci.psm1; Start-PSBuild -CI — Debug build passed; the optional Pester restore reported that PSGallery was unavailable.
• Import-Module .\tools\ci.psm1; Start-PSBuild -Configuration Release -NoPSModuleRestore — passed.
• Focused Pester 5 run for falls back when the clipboard helper times out — passed, 1/1.
• Focused Pester 5 run for pwsh updates PATH correctly even if PATH is not defined — passed, 1/1.
• Pester 4 run of Import-Module.Tests.ps1 — both changed executable-manifest cases passed; 25 passed and one unrelated existing GAC expectation failed.
• Focused startup assembly test — the revised assertion correctly rejected separate unexpected assemblies in the local Windows build; the reported RC defect involving only missing historical assemblies is no longer a failure condition.
• PowerShell parser validation for all changed .ps1 and .psm1 files — passed.
• ModulePath.Tests.ps1 and the affected implicit-remoting Describe were not run because this session is not elevated.

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. If this PR is a work in progress, please open this as a Draft Pull Request and mark it as Ready to Review when it is ready to merge.
• Breaking changes
  • None
  • OR
  • Experimental feature(s) needed
    • Experimental feature name(s):
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed