dsh-system-prompt: DeepSeek Harness System Prompt Editing and Rollback Tool

`dsh-system-prompt` is a plugin for DeepSeek Harness that allows managing system prompts on the settings page, solving the issue of being unable to easily roll back changes. It supports three modes—default, instruction appending, and full replacement—and provides features such as loading defaults, previewing, undoing changes, and restoring defaults. The plugin has a 100,000-character text limit, stores its configuration in DSH settings, and retains those settings after uninstallation.