Bring in the CI fixes that landed after this branch was cut, so the
pipeline can actually exercise the pkg_resources change.

Both jobs on this PR (run 31264233541, 8 Aug) failed in "Test with
python-ace with tensorpotential". The logs are not readable without admin
rights, but the failure is pre-existing and not from this branch: the
sibling PR #103 (run 31264271622) failed in the same step on the same day
off the same base, and 3bfa4df records that failure as

    pyace/activelearning.py:9: from maxvolpy.maxvol import maxvol
    E ModuleNotFoundError: No module named 'maxvolpy'
    Interrupted: 2 errors during collection

i.e. no test ran at all. Master has since fixed it:

  * 3bfa4df installs lib/maxvolpy explicitly, because `pip install .`
    builds a wheel and never runs setup.py's InstallMaxVolPyLocalPackage
    hook, so the suite could not be collected at all. This branch's run
    predates that step existing in the workflow.
  * d63466f imports UnitCellFilter from ase.filters with a fallback to
    ase.constraints; that was the sole remaining failure once collection
    worked, and it only affected the 3.10 job.

Merge is clean. Both sides touch bin/pacemaker in different hunks - the
import block here, the cutoff deprecation from f366916 further down - and
both survived intact.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>