Fix markdown rendering in Introduction and Historical Context sections

Apply markdown filter to Introduction and Historical Context sections
to properly render bold text and other markdown formatting.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

kjvstudy_org/templates/book.html

@@ -346,9 +346,7 @@ document.addEventListener('DOMContentLoaded', function() {
 {% if book_intro and book_intro.introduction %}
 <section>
     <h2>Introduction</h2>
-    {% for paragraph in book_intro.introduction.split('\n\n') %}
-    <p>{{ paragraph }}</p>
-    {% endfor %}
+    {{ book_intro.introduction|md|safe }}
 </section>
 {% elif introduction %}
 <section>
@@ -412,9 +410,7 @@ document.addEventListener('DOMContentLoaded', function() {
 {% if book_intro and book_intro.historical_context %}
 <section>
     <h2>Historical Context</h2>
-    {% for paragraph in book_intro.historical_context.split('\n\n') %}
-    <p>{{ paragraph }}</p>
-    {% endfor %}
+    {{ book_intro.historical_context|md|safe }}
 </section>
 {% elif historical_context %}
 <section>