ci: Enforce Black formatting

Add Github Actions workflow to enforce Black formatting rules

.github/workflows/black.yml

@@ -0,0 +1,14 @@
+name: Formatting
+
+on: [push, pull_request]
+
+jobs:
+  black:
+    runs-on: ubuntu-latest
+    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
+    steps:
+      - uses: actions/checkout@v4
+      - uses: psf/black@stable
+        with:
+          options: "--check --verbose"
+          src: "./src ./tests"