vizcb-codeblock-visualizer: DeepSeek Harness Chart Rendering and Preview

`vizcb-codeblock-visualizer` is a DeepSeek Harness plugin that automatically renders SVG, HTML, and Mermaid code blocks from model output into interactive chart cards and provides file preview functionality. The plugin uses the host-side DOMPurify and Mermaid Worker to ensure secure rendering, supports caption extraction, full-screen viewing, and export, and addresses concurrent request batching and caching. Installation and configuration are straightforward, and it requires adherence to the specified output format for alternating text and graphics.