fix(nav): ensure nav bar appears above tutorial tooltips

Increased navigation bar z-index from 30 to 1000 to ensure it remains
above tutorial tooltips (which use z-index 50 and 100) when scrolling.

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

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

apps/web/src/components/AppNavBar.tsx

@@ -584,7 +584,7 @@ export function AppNavBar({ variant = 'full', navSlot }: AppNavBarProps) {
           top: 0,
           left: 0,
           right: 0,
-          zIndex: 30,
+          zIndex: 1000,
           transition: 'all 0.3s ease',
         })}
       >