feat(dashboard): render debug analysis content as markdown

[aaight]

Summary

• Installs react-markdown and @tailwindcss/typography in the web frontend to enable proper markdown rendering
• Registers the Tailwind typography plugin via the @plugin CSS directive in web/src/index.css
• Replaces the verbatim <pre> rendering in the Section component of debug-analysis.tsx with <ReactMarkdown> wrapped in a styled <div> using prose prose-sm dark:prose-invert max-w-none

Card: https://trello.com/c/OvpXauKM/177-lets-have-debug-analysis-contents-in-dashboard-ui-rendered-and-displayed-nicely-as-markdown-since-they-are-markdown-now-they-are

Test plan

• Navigate to a run detail page → Debug Analysis tab with an existing analysis
• Confirm summary, issues, rootCause, timeline, and recommendations sections render as formatted markdown (headings, lists, bold/italic text, etc.)
• Toggle between light and dark mode — confirm prose-invert provides proper readable contrast in dark mode
• Confirm Re-run Analysis button still works
• Confirm no layout overflow issues (content fills section width via max-w-none)
• Confirm loading, running, and no-data states are unaffected

🤖 Generated with Claude Code

[nhopeatall]

LGTM — Clean, well-scoped change. The react-markdown + @tailwindcss/typography combination is the standard approach for rendering markdown in a Tailwind-based React app. Key things verified:

• Tailwind v4 compatibility: @tailwindcss/typography v0.5.19 explicitly supports Tailwind v4 in its peer deps, and the @plugin directive is the correct v4 registration syntax.
• Security: react-markdown strips raw HTML by default (no rehype-raw plugin used), so there's no XSS risk even if the LLM-generated analysis content contains HTML.
• Styling: prose prose-sm dark:prose-invert max-w-none is idiomatic usage — max-w-none prevents unwanted width constraints, prose-sm matches the existing text-sm sizing, and dark:prose-invert handles dark mode.
• CI: All checks pass.