feat: render benchmark answers as Markdown

[farhan-helmy]

Summary

Benchmark answers now render as readable Markdown instead of dense 12px raw text. The answer browser uses 16px typography, preserves the exact source behind a Raw Markdown disclosure, and keeps model-supplied HTML and unsafe links inert.

The renderer covers the structures that occur in the published results: headings, bold and italic text, ordered and unordered lists, quotes, tables, links, inline code, and fenced code blocks.

Validation

• 12 site tests pass.
• The production static build completes successfully.
• JavaScript syntax and diff checks pass.
• Desktop and mobile answer-browser layouts were inspected.
• Browser coverage verifies exact raw output, non-default ordered-list starts, escaped emphasis, safe HTTPS links, blocked javascript: and data: links, and inert hostile HTML.
• Code review completed and all actionable findings were applied (20260819-160738-dccad3e3).

Post-Deploy Monitoring & Validation

• Owner and window: PR author, immediately after the GitHub Pages deployment completes.
• Watch: the Pages deployment job and the live answer-browser URL.
• Search for: failed deploy steps, browser console TypeError, and answer-loading errors.
• Healthy signal: the live page returns HTTP 200, answer cards contain .markdown-body, formatted text is visible at the larger size, and Raw Markdown opens with the original content.
• Failure signal: answers stay on a loading state, render as unformatted delimiters, or produce console errors. Revert this PR to restore the previous raw-text renderer.

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