Fix sidenote selection highlight showing through

Added vendor prefixes for user-select and transparent
selection background to prevent sidenotes from showing
blue highlight when selecting verse text.

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

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

kjvstudy_org/templates/chapter.html

@@ -48,6 +48,16 @@
     transition: all 0.3s ease;
     position: relative;
     user-select: none;
+    -webkit-user-select: none;
+    -moz-user-select: none;
+    -ms-user-select: none;
+}
+
+.sidenote::selection,
+.marginnote::selection,
+.sidenote *::selection,
+.marginnote *::selection {
+    background: transparent;
 }
 
 label.sidenote-number {