Clean up beads-mcp .gitignore

- Add .pytest_cache/ to ignored test artifacts
- Reorganize sections for clarity
- Move .coverage to testing artifacts section

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

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

integrations/beads-mcp/.gitignore

@@ -6,9 +6,12 @@ wheels/
 *.egg-info
 __pycache__
 
+# Testing artifacts
+.pytest_cache/
+.coverage
+
 # Virtual environments
 .venv
 /.env
 /CLAUDE.md
 /TODO.md
-/.coverage