alexei.dolgolyov
3b683ce82c
Two wins:
* actions/setup-python's built-in pip cache, keyed on the two
pyproject.toml files, turns the 20+ transitive dep downloads into
a single tarball restore on cache hit.
* One ``pip install -e ./core -e ./server[dev]`` call instead of
two — lets pip's resolver run once over the combined graph and
skips the second invocation's overhead.
Also dropped ``pip install --upgrade pip``: the runner image already
ships a recent pip, and the upgrade ran once per CI job for no gain.