docs: add English quick reference to help

templates/help_index.html

@@ -40,6 +40,9 @@
       </div>
       <nav class="help-nav" aria-label="Help navigation">
         <a href="{{ url_for('index') }}">Calculator</a>
+        <a href="{{ url_for('user_manual') }}">User Manual</a>
+        <a href="{{ url_for('quick_reference') }}">Quick Reference</a>
+        <a href="{{ url_for('recent_changes') }}">Recent Changes</a>
       </nav>
     </div>
   </header>
@@ -57,6 +60,13 @@
         </p>
         <a href="{{ url_for('user_manual') }}">Open User Manual</a>
       </article>
+      <article class="help-card">
+        <h2>Quick Reference</h2>
+        <p>
+          Concise English reference for the most common RollCalc workflows and result interpretations.
+        </p>
+        <a href="{{ url_for('quick_reference') }}">Open Quick Reference</a>
+      </article>
       <article class="help-card">
         <h2>Recent Changes</h2>
         <p>