Hide sidebar fully on mobile, remove breadcrumb drop shadow

- Push collapsed sidebar further off-screen (-165px)
- Remove box-shadow from sticky breadcrumb

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

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

kjvstudy_org/templates/base.html

@@ -376,13 +376,13 @@
         }
 
         .breadcrumb.stuck {
-            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
+            box-shadow: none;
             padding-top: 0.75rem;
             margin-top: 0;
         }
 
         [data-theme="dark"] .breadcrumb.stuck {
-            box-shadow: 0 2px 8px rgba(0,0,0,0.2);
+            box-shadow: none;
         }
 
         .breadcrumb-actions {
@@ -1024,7 +1024,7 @@
         @media (max-width: 768px) {
             .nav-sidebar {
                 width: 140px;
-                left: -140px;
+                left: -165px;
                 top: 0;
                 bottom: 0;
                 max-height: 100vh;