dsh-url-router: Adding Addressability to the DSH Web GUI

dsh-url-router is a plugin designed specifically for the DeepSeek Harness (DSH) Web GUI, intended to solve the problem that dynamic views cannot be shared or revisited via URLs. Acting as the sole writer to the address bar, it maps the current interface by modifying the URL fragment (the part after `#`), ensuring that every view (session, panel, task, etc.) has an independent, addressable link. The plugin features zero dependencies, preserves initial parameters, and does not pollute browser history. Users can right-click or middle-click a list row to open the corresponding link directly in a new tab. However, note that this plugin is mutually exclusive with other plugins that modify the URL fragment, and it only supports views already rendered on screen; virtualized, unrendered content is not supported.