Add chronology methodology note to biblical timeline

Display explanation of successive method of reckoning used for Genesis 5 & 11
genealogies. The note clarifies that 'begat' (Hebrew yalad) may indicate either
direct father-son relationships (marked by 'he named him') or ancestral lines
with potential gaps. Changed intro from 'approximate dates' to 'calculated dates'
to reflect precision of Ussher chronology.

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

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

kjvstudy_org/templates/biblical_timeline.html

@@ -8,7 +8,13 @@
 <p class="subtitle">Major events from Creation to the early Church</p>
 
 <section>
-    <p>This timeline presents key events of biblical history with approximate dates and relevant scripture references.</p>
+    <p>This timeline presents key events of biblical history with calculated dates and relevant scripture references.</p>
+
+    {% if chronology_note %}
+    <p style="font-size: 0.95rem; color: #555; margin-top: 1.5rem; padding: 1rem; background: #f9f9f9; border-left: 3px solid #666;">
+        {{ chronology_note | safe }}
+    </p>
+    {% endif %}
 </section>
 
 {% for period_name, events in timeline_events.items() %}