fix(deps): declare setuptools in dev extra for packaging tests (#34851)

* fix(deps): declare setuptools in dev extra for packaging tests

tests/test_packaging_metadata.py imports `from setuptools import
find_packages` at module scope to validate package discovery against
the live tree. setuptools was being picked up ambiently from the CI
runner image, but recent ubuntu-latest images no longer ship it in the
test venv, so collection fails with ModuleNotFoundError on every PR.

Declare setuptools==82.0.1 in the dev optional-dependencies so `.[all,dev]`
installs it explicitly rather than relying on the runner environment.

* test(packaging): skip packaging-metadata tests when setuptools absent

Belt-and-suspenders alongside declaring setuptools in [dev]: guard the
module-level `from setuptools import find_packages` with
pytest.importorskip so a runner missing setuptools SKIPS these checks
instead of erroring out collection for the entire test shard.

* chore(deps): sync uv.lock for setuptools dev dependency

tests/test_packaging_metadata.py

@@ -1,7 +1,14 @@
 from pathlib import Path
 import tomllib
 
-from setuptools import find_packages
+import pytest
+
+# setuptools is declared in the [dev] extra and is the build backend, but
+# guard the import so a runner without it skips these packaging checks
+# instead of erroring out collection for the whole shard (it used to be
+# picked up ambiently from the CI image; newer ubuntu-latest images don't
+# ship it in the test venv).
+find_packages = pytest.importorskip("setuptools", exc_type=ImportError).find_packages
 
 
 REPO_ROOT = Path(__file__).resolve().parents[1]