next-mdx-remote evaluates MDX at runtime with a different React version
than Next.js 16's internal canary, causing build failures. Switch to
@next/mdx which compiles MDX through Next.js's own bundler pipeline.
- Replace next-mdx-remote with @next/mdx, @mdx-js/mdx, @mdx-js/loader
- Use dynamic imports for blog MDX files instead of MDXRemote
- Add remark-frontmatter so compiler skips YAML frontmatter blocks
- Gate cache/CSP headers to production only (immutable dev chunks
were poisoning browser cache)
Made-with: Cursor
