gh-watch: A GitHub PR/Issue Change Monitoring Plugin for DSH

gh-watch is a GitHub monitoring plugin for DeepSeek Harness (DSH). It polls target repositories in the background, automatically detects PR and issue changes, and notifies the AI. It supports per-session configuration, exponential backoff retries, and a baseline snapshot mechanism to avoid flooding the session with historical data. The plugin is responsible only for discovery and notification; it does not perform code review or merging. Users can use tools such as `gh_watch_configure` to configure the watcher, proactively query its status, and acknowledge notifications. This plugin aims to reduce development complexity in multi-AI collaboration scenarios and separate discovery from decision-making.