DeepSeek Harness Web Access Authentication Plugin

The official DeepSeek Harness (DSH) Web profile has no authentication by default. After installation and restart, this plugin adds local Token and Cookie-based access authentication for local development environments. A Token must be obtained via a link on first use, after which direct access is available. The plugin enforces local-IP binding and provides HTTP- and WebSocket-level security protections, returning 401 for sensitive endpoints and 403 for mismatched request headers. It is only compatible with specific DSH versions, does not support LAN or public network deployment, and a failed installation will cause the profile to fail to start.