Workspace Compilation Follow-up - Add support for BCPT and Upgrade Tests

[aholstrup1]

❔What, Why & How

This PR addresses a few follow-up items for supporting workspace compilation. Specifically

• Adds support for upgrade tests
• Adds support for compiling BCPT apps

Related to AB#620485 and AB#620310

✅ Checklist

• Add tests (E2E, unit tests)
• Update RELEASENOTES.md
• Update documentation (e.g. for new settings or scenarios)
• Add telemetry

[Copilot]

Pull request overview

Adds missing pieces to workspace compilation so upgrade testing and AppSourceCop baselines can use previous-release apps, and extends workspace compilation to BCPT test folders.

Changes:

• Introduces a new DownloadPreviousRelease composite action and wires it into project build templates.
• Passes previousAppsPath through CompileApps and RunPipeline, and updates logic to consume previously-downloaded apps for upgrade scenarios.
• Adds New-AppSourceCopJson generation and BCPT compilation support, plus updates docs and tests.

Reviewed changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
Tests/DownloadPreviousRelease.Action.Test.ps1	Adds a compile/yaml-contract test for the new action
Tests/DetermineProjectsToBuild.Test.ps1	Minor test adjustment in project build determination
Tests/CompileFromWorkspace.Test.ps1	Adds unit tests for New-AppSourceCopJson behavior
Templates/Per Tenant Extension/.github/workflows/_BuildALGoProject.yaml	Downloads previous release and forwards previousAppsPath
Templates/AppSource App/.github/workflows/_BuildALGoProject.yaml	Downloads previous release and forwards previousAppsPath
Scenarios/settings.md	Updates workspace compilation documentation/requirements
Actions/RunPipeline/action.yaml	Adds previousAppsPath input and forwards it to script
Actions/RunPipeline/RunPipeline.ps1	Consumes previousAppsPath for upgrade testing; adjusts workspace compilation folder handling
Actions/DownloadPreviousRelease/action.yaml	New composite action definition
Actions/DownloadPreviousRelease/README.md	New action documentation
Actions/DownloadPreviousRelease/DownloadPreviousRelease.ps1	Implements previous release discovery/download and outputs path
Actions/CompileApps/action.yaml	Adds previousAppsPath input and forwards it to script
Actions/CompileApps/Compile.ps1	Uses previous apps for AppSourceCop baseline and compiles BCPT folders
Actions/.Modules/CompileFromWorkspace.psm1	Adds New-AppSourceCopJson and exports it

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.