Migration: aspire-resourcekit

Migration: aspire-resourcekit

This repository currently contains a vendored copy of build/PipelineCLI. Migrate it as follows.

1. Replace the vendored build/PipelineCLI with the shared Purview.Build tool pinned to the chosen released version.
2. Add this purview-build.json:

{
  "Build": {
    "Solution": "src/ResourceKit.slnx",
    "TestRoot": "src/tests",
    "TestPatterns": "*Tests.csproj",
    "TestFilter": "/*/*/*/*[Category=Unit]"
  },
  "Release": { "Mode": "None" }
}

3. Replace pr.yml and release.yml with thin callers of purview-dev/build/.github/workflows/purview-build.yml and .../purview-release.yml, passing build-version. Keep the [Category=Unit] filter in the release caller.
4. In the release caller set release-mode: NuGet and secrets: inherit (NUGET_APIKEY and GITHUB_TOKEN are read by the shared workflow).
5. Run the PR pipeline, then delete build/PipelineCLI and its pipeline-only central package declarations (ModularPipelines*, NuGet.Packaging/Versioning).

The old solution path and unit-test filter are preserved exactly. Other repositories migrate by changing only the JSON paths/patterns; for example dotnet-project-sdk can list unit and integration project globs in Build:TestPatterns.