Clean up infrastructure: remove dead code, fix watch script, fix typos

- Remove hugo.sh (broken draft superseded by hugo-new.sh)
- Remove unused mermaid shortcode and partial (only code-block
  rendering via render-codeblock-mermaid.html is used)
- Remove dead xparams.mermaid check from extend_head.html
- Fix watch-rmd.sh to pass shared libs args matching the Makefile
- Fix typos in Makefile ("permsions", "Publising")

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/watch-rmd.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 WATCH_DIR="content/posts"
+PROJECT_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+LIBS_DIR="static/libs"
+LIBS_URL="/libs"
 
 echo "🚨 Watching ${WATCH_DIR} for changes..."
 
@@ -9,7 +12,7 @@ inotifywait -m -e close_write --format '%w%f' -r "$WATCH_DIR" | while read FILE;
 
         echo "🔄 Change detected in $FILE. Rendering..."
 
-        (cd "$POST_DIR" && Rscript -e 'renv::restore(prompt = FALSE); statdown::statdown_render("index.Rmd")')
+        (cd "$POST_DIR" && Rscript -e 'renv::restore(prompt = FALSE); statdown::statdown_render("index.Rmd", output_root = "'"${PROJECT_ROOT}/${LIBS_DIR}"'", url_root = "'"${LIBS_URL}"'")')
 
         echo "✅ Rendered ${FILE}"
     fi