chore(gitignore): ignore transient Claude Code agent worktrees

.claude/worktrees/ holds throwaway git worktrees used by background agents;
never commit them.

https://claude.ai/code/session_01PgHpCFzwYB7Qy9L6kmR8CE

Author: claude

.gitignore

@@ -93,3 +93,6 @@ deps/
 .cache/
 build/
 dist/
+
+# Claude Code — transient agent worktrees (never committed)
+.claude/worktrees/