Lägg till pytest coverage-filer i .gitignore

- .coverage (coverage data file)
- htmlcov/ (HTML coverage report)
- .pytest_cache/ (pytest cache)

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: marcarl

.gitignore

@@ -3,6 +3,11 @@ ___pycache__
 *.pyc
 .DS_Store
 
+# Test coverage
+.coverage
+htmlcov/
+.pytest_cache/
+
 # Ignore output files
 logs/
 output/