Fix GitHub Actions workflow issues

- Add black configuration to exclude old/ and notebooks/ directories
- Update workflow to trigger on pushes to release branch (fixes badge)
- This resolves formatting failures in CI

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: djfrancesco

.github/workflows/tests.yml

@@ -1,6 +1,9 @@
 name: Run tests and upload coverage
 
 on:
+  push:
+    branches: 
+      - release
   release:
     types: [created]
 

pyproject.toml

@@ -68,6 +68,14 @@ testpaths = [
     "tests"
 ]
 
+[tool.black]
+extend-exclude = '''
+/(
+    old
+    | notebooks
+)/
+'''
+
 [tool.cibuildwheel]
 # Skip 32-bit i686 architectures (outdated, rarely needed)
 skip = "*_i686"