v0.2.1

Changed

• wtclone rm now detects gitignored entries (caches, build artifacts, vendored deps) before delegating to git worktree remove. These pass git's cleanliness check but block the final rmdir with the cryptic failed to delete '...': Directory not empty. The new pre-check fails with a message that names the offending entries and points to the two remediation paths: wtclone rm <branch> --force, or git -C <wt_path> clean -fdX to clean first. Behavior is unchanged — --force still bypasses the check.
• wtclone add now diagnoses the "branch already exists locally" failure with a tailored message per case: (1) branch checked out in another worktree (shows the worktree path); (2) orphan ref matching origin/<branch> (suggests the safe git worktree add <branch> attach); (3) orphan ref diverged from origin (reports ahead/behind counts and offers both attach-and-keep and branch -D + recreate paths); (4) orphan ref with no remote counterpart (suggests local-only attach). The fetch origin step now runs before the existing-branch check so the diagnosis works against fresh remote-tracking refs.