dsh-editor: A VS Code-Style Code Editor in DeepSeek Harness

DeepSeek Harness (DSH) introduces the `dsh-editor` plugin, designed to integrate the core VS Code experience into the Web interface and address the limitations of code operations within a single session window. The plugin adds a file tab to the main area and provides features such as a file tree, a Monaco editor with multi-tab, syntax highlighting, and Minimap support, ripgrep-based cross-file search, Markdown preview, and Git status management. Users can quickly open files with `Ctrl+P` or `Ctrl+click` a path in the conversation to jump directly to it. The plugin supports installation from GitHub, locally, or via npm, and requires a DSH restart after installation.