Ignore .claude/worktrees/ (background-agent scratch space)

Not project content — a locked git worktree the rename agent uses for
isolation, so it shouldn't show up as untracked or get committed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0164eTtmmq6U8GQkAEmQsvV5

Author: claude

.gitignore

@@ -5,3 +5,4 @@ coverage/
 .DS_Store
 .vite/
 .vercel
+.claude/worktrees/