dsh-launcher: A One-Click Launcher Plugin for DSH Web

The `dsh-launcher` plugin is designed to address the issue of manually starting services interrupting the workflow during DeepSeek Harness (DSH) development. By generating launch scripts, automatically checking service status, starting services with one click and opening the browser, and supporting desktop shortcuts and custom icons, it provides a convenient local service startup solution for Windows environments. After installation, it can be configured in the DSH settings panel or invoked by AI tools to generate scripts.