- Add lol_html-based HTML whitespace minifier (utils/html_minify.rs)
that collapses whitespace and strips comments while preserving
<pre>, <code>, <textarea>, <script>, <style> content
- Add Axum middleware (middleware/minify_html.rs) that minifies
text/html responses with per-URL moka cache (256 entries, 300s TTL)
- Wire middleware into the server router in main.rs
- Add CSS minifier to generate_highlight_css build step
- Apply minify_html to rendered markdown output and TOC
- Add http-body-util dependency for body collection in middleware
