Extend .gitignore with additional exclusions

- .claude/ (Claude Code local settings)
- *.log (log files)
- .DS_Store (macOS system files)

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

.gitignore

@@ -2,3 +2,6 @@ node_modules/
 .env
 data/*.db
 docs/
+.claude/
+*.log
+.DS_Store