dsh-vscode-theme: Importing VS Code Themes for DeepSeek Harness Web

The `dsh-vscode-theme` extension allows users to import VS Code `.vsix` theme files into the DeepSeek Harness (DSH) Web interface. The extension parses files locally in the browser, without uploading them to any server, and maps the VS Code workbench color palette to DSH UI tokens. Users can import a theme by dragging and dropping it through the Web interface, or use the `vscode_theme_parse` tool via an agent proxy to parse theme details. Note that this extension only maps interface colors; syntax token colors are intended exclusively for use by the agent parser.