Add .claude/worktrees to .gitignore (#528)

## Summary
- Add `.claude/worktrees/` to `.gitignore` to prevent Claude Code
worktree directories from being tracked

## Test plan
- [x] Verify `.claude/worktrees/` directories are ignored by git

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

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: cpcloud

.gitignore

@@ -38,3 +38,6 @@ tmp/
 REPORT.md
 .zed
 .superset
+
+# Claude Code worktrees
+.claude/worktrees/