_html: Ask Perl to parse every and only QStags

qsgen2

@@ -803,7 +803,7 @@ function _html() {
     if ${debug}; then _msg debug "_html: Converting QStags in content"; fi
 
     # Convert QStags to HTML using Perl, strictly matching the QStags list
-    local html_content=$(echo "${content}" | perl -pe '
+    local html_content=$(echo "${content}" | perl  -0777 -pe '
         BEGIN {
             # Define a hash of QStags to their HTML equivalents
             %qstags = (
@@ -843,7 +843,7 @@ function _html() {
         }
         while (my ($key, $value) = each %qstags) {
             $key = quotemeta($key); # Escape special characters in QStags
-            s/(?<!\S)$key\b/$value/gi;
+            s/(?<!\S)\Q$key\E\b/$value/g;
         }
     ');