dsh-tui-market: dsh-TUI Plugin Marketplace Plugin

dsh-tui-market is a native plugin marketplace built for DeepSeek Harness (DSH), designed to enable plugin browsing, searching, installation, and uninstallation within the TUI via the `/market` command, eliminating the need to switch to an external terminal as before. Built around the GitHub topic `dsh-plugin`, the plugin supports viewing curated lists, global rankings, and locally installed plugins, and can directly install from npm or GitHub-formatted sources. Since it runs using subprocesses, it introduces no runtime dependencies. Installation requires packaging from source and startup with the `--profile` parameter, followed by restarting the TUI for the installation to take effect.