Add coverage files to .gitignore

Added coverage-related files to .gitignore:
- .coverage (coverage database)
- .coverage.* (coverage data files)
- htmlcov/ (HTML coverage reports)
- coverage.xml (XML coverage reports)
- .cache (pytest cache)

https://claude.ai/code/session_01B9dpKXH8wbD7MPtPBDHrjq

.gitignore

@@ -46,6 +46,13 @@ ENV/
 *.egg-info/
 .pytest_cache/
 
+# Coverage
+.coverage
+.coverage.*
+htmlcov/
+coverage.xml
+.cache
+
 # Next.js
 .next/
 out/