dsh-flakefinder: A Test Stability Plugin for DeepSeek Harness

`dsh-flakefinder` is a test stability plugin for DeepSeek Harness, designed to distinguish code errors from unstable flaky tests. It helps developers manage their testing environments by repeatedly running tests, recording history, and maintaining quarantine lists. The plugin has zero runtime dependencies, supports multiple frameworks, and provides core tools such as `flaky_detect` and `flaky_quarantine`. Agents can quickly locate and quarantine unstable test cases through interactive commands. It requires Node.js 22.19+ and the service must be restarted after uninstallation.