dsh-repro: Generate replayable problem packages for DeepSeek Harness

dsh-repro is an MIT-licensed plugin for DeepSeek Harness designed to address the conflict between leaking credentials in session troubleshooting and the lack of runtime context. It provides a `/repro` command that reads complete logs from the current session. It performs value-level cleaning on suspicious credentials (such as high-entropy strings and specific prefix tokens) using a "fail-closed" strategy, and collects failed commands along with git diffs to ultimately generate a shareable and replayable issue package in JSON format. This package includes cleaned logs, failed commands, and difference information, which can be replayed later using `ctx.sessions.create`. The plugin requires mounting the `commands` and `sessionPersistence` services, while `subprocess` is an optional dependency.