ci: pin black 26.3.1 across pre-commit and CI, drop Python 3.13

.github/workflows/ci.yml

@@ -11,24 +11,19 @@ jobs:
   blocking-checks:
     name: Blocking Tests & Quality Checks
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ['3.12', '3.13']
-
     steps:
       - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
-          python-version: ${{ matrix.python-version }}
+          python-version: '3.12'
 
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
           pip install -e ".[dev]"
+          pip install "black==26.3.1"
 
-      # Run code quality checks (only on one Python version to save time)
       - name: Code Quality Checks
-        if: matrix.python-version == '3.13'
         run: |
           black --check .
           isort --check .
@@ -51,7 +46,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
-          python-version: '3.13'
+          python-version: '3.12'
 
       - name: Install dependencies
         run: |
@@ -82,7 +77,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
-          python-version: '3.13'
+          python-version: '3.12'
 
       - name: Install and test
         run: |
@@ -107,7 +102,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
-          python-version: '3.13'
+          python-version: '3.12'
 
       - name: Install dependencies
         run: |

.pre-commit-config.yaml

@@ -18,7 +18,7 @@ repos:
       - id: actionlint
 
   - repo: https://github.com/psf/black
-    rev: 25.11.0
+    rev: 26.3.1
     hooks:
       - id: black
         language_version: python3.12