Add LaTeX math support to blog posts

Summary

Add LaTeX/KaTeX math rendering support to the MarkdownFormatter component for blog posts.

Reference Implementation

A WIP implementation exists in commit 074437a9 on the rail-fares-freeze branch. This commit:

• Adds remark-math and rehype-katex plugins (already installed as dependencies)
• Imports KaTeX CSS
• Adds test suite for math rendering

Issues to Address

1. Display math not working: Block-level math with $$...$$ doesn't render correctly
2. Dollar sign conflicts: Enabling remark-math means $ signs in currency amounts (e.g., $100) would need to be escaped as \$. This is problematic for a policy blog that frequently references currency.

Potential Solutions

1. Use a different syntax for math (e.g., $$$...$$$ or :math:...::)
2. Configure remark-math to use different delimiters
3. Only enable math support for specific posts via frontmatter flag
4. Use code fences with math language identifier

Related

• Commit: 074437a9 (will be reverted from rail-fares-freeze branch)

Start with the MarkdownFormatter component and inspect commit 074437a9 on the rail-fares-freeze branch, including its math rendering test suite. Compare the proposed delimiter and frontmatter options, then verify that block math renders correctly without breaking currency amounts such as $100. Done means the chosen syntax works for blog posts and the relevant tests pass.