Fix release deploy job for pyproject/setuptools-scm packaging

[Copilot]

The deploy GitHub Actions job failed in the release workflow because it still attempted to edit setup.py, which no longer exists in this pyproject-based package. This PR updates version injection to the setuptools-scm path used by the current build system.

• Workflow fix: replace obsolete setup.py mutation

  • Removed the tag extraction + sed ... setup.py step.
  • Added a single step that exports the release version via SETUPTOOLS_SCM_PRETEND_VERSION from GITHUB_REF_NAME (with optional v prefix stripped).

• Build path alignment with current packaging

  • Keeps python -m build and publish steps unchanged.
  • Ensures release builds resolve the intended version without relying on legacy setup.py mechanics.

- name: Set package version from tag
  run: echo "SETUPTOOLS_SCM_PRETEND_VERSION=${GITHUB_REF_NAME#v}" >> "$GITHUB_ENV"