Repin onto the published stapel-core 0.8.0 per library-standard §7:
- one minor window >=0.8,<0.9 (§7.1; floor 0.8.0 is on PyPI — no pin into the void)
- add the release-track CI job (§7.4): installs as an end user (pip install .,
  deps from PyPI by pin, no git-main core / no editable siblings), asserts core
  resolves in the 0.8 window, import smoke. Advisory until the whole graph is on
  PyPI; then it becomes the blocking vX.Y.Z release gate.
- patch bump to 0.3.8 + CHANGELOG.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>