Update markdown preview test loader for spatial helpers

Add spatial HTML preview mode using grounding boxes

Add HTML+MathJax preview panel with source view

Preserve OCR line breaks in markdown preview

Fix markdown preview math replacement inside code blocks

Fix MathML rendering: placeholder approach + HTML escaping + \frac OCR fix

Replace browser-side KaTeX/MathJax with server-side MathML via latex2mathml

Fix aligned environments breaking KaTeX: collapse math to single line

Replace MathJax+gr.HTML with gr.Markdown+KaTeX for reliable math rendering

Fix LaTeX display and add quality-of-life improvements

Fix Space metadata: suggested_hardware not hardware

Add hardware: zero-gpu to Space metadata

Fix Gradio 6 compatibility: move head to launch(), disable SSR

Fix attn_impl fallback: use eager not sdpa on ZeroGPU

Fix flash_attention_2 startup crash on ZeroGPU and LaTeX delimiter rendering

Initial commit — DeepSeek-OCR-2 Math Rendering Edition