Add packaging group; fix dev group; fix python-packaging workflow call

The packaging dependency group was missing entirely. The dev group was
missing packaging and wheels. The python-packaging workflow was being
called with working-directory (a job-level key, silently ignored in
workflow_call) instead of the correct pyproject-directory input.

Remove wheels from dev dependency group

Update uv.lock

Author: jeromekelleher

.github/workflows/tests.yml

@@ -13,9 +13,9 @@ jobs:
 
   packaging:
     name: Python packaging
-    uses: tskit-dev/.github/.github/workflows/python-packaging.yml@v4
+    uses: tskit-dev/.github/.github/workflows/python-packaging.yml@main
     with:
-      working-directory: python
+      pyproject-directory: python
       cli-test-cmd: tskit --help
 
   test-c:

python/pyproject.toml

@@ -99,6 +99,11 @@ wheels = [
   "cibuildwheel",
 ]
 
+packaging = [
+    "twine",
+    "validate-pyproject[all]",
+]
+
 # Fully pin lint requirements for determinism.
 lint = [
     "clang-format==21.1.8",
@@ -110,6 +115,7 @@ dev = [
     {include-group = "docs"},
     {include-group = "lint"},
     {include-group = "test"},
+    {include-group = "packaging"},
 ]
 
 [tool.pytest.ini_options]