fix: ci pre-commit poetry env

Install poetry before setup-python and enable the poetry cache so
setup-python activates the 3.14 interpreter. With virtualenvs.create=false
poetry otherwise installs into the runner's system Python 3.12 and fails
uninstalling Debian dist-packages.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bk6CFfaN3YJFZ6yztQja7D

.github/workflows/pre-commit.yml

@@ -15,12 +15,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+      - name: Install poetry
+        run: pipx install poetry==$POETRY_VERSION
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
           python-version: '3.14'
-      - name: Install poetry
-        run: pipx install poetry==$POETRY_VERSION
+          cache: "poetry"
       - name: Install pre-commit
         run: poetry install
       - name: Run pre-commit