Use package-scoped release tags

[Volv-G]

Summary

• switch PyPI release triggers from generic v* tags to package-scoped tags:
  • tangle-cli-v*
  • tangle-api-v*
• parse the selected package from GITHUB_REF_NAME
• require the tag version to match that package's pyproject.toml version
• publish only the selected package's artifacts, with the PyPI version-existence guard from Publish release artifacts by package version #24 as a safety net

Intentional behavior change

This intentionally drops the generic v* release trigger. Independent package releases are expected to be common, so the tag now expresses release intent directly. A tag like v0.1.1 will no longer trigger PyPI publishing; use tangle-cli-v0.1.1 or tangle-api-v0.1.0 instead.

Testing

• GITHUB_REF_NAME=tangle-cli-v0.1.1 publish-plan simulation → selects tangle-cli, confirms version 0.1.1, skips because it exists on PyPI
• GITHUB_REF_NAME=tangle-api-v0.1.0 publish-plan simulation → selects tangle-api, confirms version 0.1.0, skips because it exists on PyPI
• GITHUB_REF_NAME=tangle-cli-v99.99.99 publish-plan simulation → fails because tag version does not match root pyproject.toml
• GITHUB_REF_NAME=v0.1.1 publish-plan simulation → fails as unsupported
• actionlint .github/workflows/release.yaml