fix: correct AppLayout flex direction to prevent content hanging on right side

Changed flex container from horizontal (default) to vertical (flex-col) to properly
stack navbar and main content. This fixes the layout issue where content was
hanging on the right side of the window.

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

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

components/layout/AppLayout.tsx

@@ -5,7 +5,7 @@ import { Navbar } from './Navbar';
 
 export function AppLayout({ children }: { children: ReactNode }) {
   return (
-    <div className="flex min-h-screen">
+    <div className="flex flex-col min-h-screen">
       <Navbar />
       <main className="flex-1 container mx-auto px-4 py-8">{children}</main>
     </div>