chore: add .coverage and htmlcov/ to .gitignore

Standard pytest-cov artefacts were missing from the ignore list.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tanem

.gitignore

@@ -18,6 +18,8 @@ build/
 .pytest_cache/
 .mypy_cache/
 .ruff_cache/
+.coverage
+htmlcov/
 
 # uv
 .python-version