Fix dropdown z-index with CSS layer forcing

Added CSS properties to force dropdown above stacking contexts:
- z-index: 99999 \!important
- position: absolute
- transform: translateZ(0) to create new stacking context
- will-change: transform for optimization

This addresses the issue where backdrop-filter in .glass creates
stacking contexts that hide dropdowns.

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

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

app/globals.css

@@ -213,6 +213,10 @@ body {
   margin-top: 4px;
   overflow: hidden;
   box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
+  z-index: 99999 !important;
+  position: absolute;
+  transform: translateZ(0);
+  will-change: transform;
 }
 
 .dropdown-item {