Add footnote markers to cross-references

Add sequential superscript numbers to cross-references on verse pages,
making them appear like traditional footnotes. Each cross-reference now
has a numbered marker (1, 2, 3, etc.) for easy reference.

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

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

kjvstudy_org/templates/verse.html

@@ -344,6 +344,7 @@
     <ul style="max-width: 60%; list-style: none; padding: 0;">
         {% for ref in cross_references %}
         <li style="margin: 1rem 0; padding-left: 1.5rem; border-left: 2px solid var(--border-color-dark);">
+            <sup style="font-size: 0.75rem; vertical-align: super; margin-right: 0.25rem;">{{ loop.index }}</sup>
             {% set ref_parts = ref.ref.rsplit(' ', 1) %}
             {% if ref_parts|length == 2 %}
                 {% set book_name = ref_parts[0] %}