CI: `pack` runs `--no-build` on a fresh checkout with nothing compiled

[beyondnetPeru]

The pack job checks out the repo and immediately runs dotnet pack … --no-build.

Because pack runs as its own job (fresh runner, and no artifacts are downloaded from build-and-test), there are no compiled binaries on disk to package. --no-build will either fail outright or produce a package with no assemblies in it.

Two valid fixes — pick one and explain the choice in the PR description:

1. Drop --no-build and let pack compile in Release.
2. Upload the build output from build-and-test as an artifact and download it in pack before packing.

Acceptance criteria

• pack completes from a clean runner.
• The resulting .nupkg contains a non-empty lib/ folder (inspect with unzip -l *.nupkg).

Where

.github/workflows/build.yml → pack job.