Enable a single '.dsc.manifests.json' file to contain many resource/extension manifests

[SteveL-MSFT]

PR Summary

This change allows for a single .dsc.manifests.json (or yaml) file to contain multiple resource or extension manifests so you no longer need a separate file per resource/extension.

No new test added as the dsctest resource now has a single manifest for all of its resources.

This turned out to be more complicated than I expected due to a known limitation in serde for handling HashMap<i32, String> which was also embedded in an enum which is now the case. To workaround this, the schema now has exitCodes be HashMap<String, String> which is what it actually is in the JSON and at runtime, we parse the key to be a i32 otherwise return an error.

Also some general code cleanup in the modified areas putting things in alpha order and modifying some code so that you get a specific error if there's invalid JSON/YAML instead of a generic error.

PR Context

FIx #1160

[Copilot]

Pull Request Overview

This PR consolidates multiple resource manifests into a single .dsc.resourcelist.json file, eliminating the need for separate files per resource. The change introduces support for resource list files that can contain an array of resource manifests, while maintaining backward compatibility with single-resource manifest files.

Key changes:

• Added ResourceManifestList struct to support arrays of resource manifests
• Updated discovery logic to handle both single and list manifest files
• Consolidated 18 separate dsctest resource manifest files into one dsctest.dsc.resourcelist.json

Reviewed Changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tools/dsctest/dsctest.dsc.resourcelist.json	New consolidated manifest file containing all dsctest resources
tools/dsctest/*.dsc.resource.json (multiple)	Removed individual resource manifest files
lib/dsc-lib/src/discovery/command_discovery.rs	Updated discovery and loading logic to support resource lists
lib/dsc-lib/src/dscresources/resource_manifest.rs	Added ResourceManifestList struct
lib/dsc-lib/src/dscerror.rs	Added InvalidManifest error variant
lib/dsc-lib/src/extensions/discover.rs	Updated extension discovery to handle manifest lists
build.ps1	Updated file copy patterns to include resourcelist files

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[SteveL-MSFT]

I'm going to update this PR based on recent discussion:

• a single container format allowing any type of valid DSC manifest in the array
• file to be called .dsc.manifestlist.json that contains a property manifests which is an array of manifests

[ThomasNieto]

Do we need to have list in the name of the file?

What about just having it be plural? dsc.manifests.json

Actually looks like that was the name of the file in the comment thread not sure why the new comment has a different name.

Was thinking that there's no reason to have separate lists for adapters, resources, extensions, etc... we could just have a single format that's an array of manifests. Perhaps .dsc.manifests.json?

[SteveL-MSFT]

@ThomasNieto the original addition for list was to make it more obvious between resource and resources, but since we've moved on from that, I think just manifests is fine. Will change.