When adding a polecat, check if the branch already exists (e.g., from a previous polecat that was removed but whose branch wasn't cleaned up). If so, reuse the existing branch with WorktreeAddExisting instead of failing with 'a branch named polecat/X already exists'. Fixes: gt-bmjw 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>