Fix sidenote color to distinguish from main text

Changed sidenotes from pure black (#000) to dark gray (#444).
Sidenotes should be visually distinct as secondary content while
maintaining good readability.

Dark mode: Changed to #aaa for appropriate contrast.

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

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

kjvstudy_org/templates/base.html

@@ -670,14 +670,14 @@
                 border-left: 4px solid #999;
                 font-size: 0.95rem;
                 line-height: 1.6;
-                color: #000;
+                color: #444;
                 font-weight: 400;
             }
 
             [data-theme="dark"] .sidenote,
             [data-theme="dark"] .marginnote {
                 border-left-color: #666;
-                color: #e0e0e0;
+                color: #aaa;
             }
 
             .sidenote-number,