@tmpdot

File-diff visualization between checkpoint time nodes for DeepSeek Harness: read-only timeline + per-file line diff over dsh-checkpoint-rewind checkpoints, as a /diff command, JSON HTTP API, and GUI panel.

Deliberately inject a small, known bug into a disposable git worktree so learners can practice finding and fixing it. A teaching tool - read the README for its educational philosophy and safety guarantees.