[MarcelT87]

Summary

Add a release-engineering smoke test for the actual built package, separate from the existing editable-install and beginner-flow coverage.

Current CI already proves pip install -e . and the full checkout-based beginner workflow. Before rc2, it should also prove that a normal sdist/wheel build contains everything required at runtime.

New CI job

The package-smoke job:

1. builds both source distribution and wheel with python -m build;
2. requires exactly one .tar.gz and one .whl;
3. creates a fresh virtual environment;
4. installs the generated wheel rather than the checkout;
5. changes to /tmp so imports cannot accidentally rely on the repository checkout;
6. verifies installed package metadata matches pyproject.toml;
7. verifies ebus-evidence --version;
8. verifies ebus-evidence --help;
9. loads the bundled hw5103-open-evidence profile and checks its expected v2 check IDs.

Because the default python -m build flow builds the wheel from the source distribution, this also catches source-distribution omissions that would prevent a valid wheel build.

Scope

CI/release validation only.

No runtime, parser, Evidence, installer, profile or submission behaviour changes. No package is uploaded or published.