Remove duplicate title and description from presentation page

- Remove title and description from pages/presentation.tsx
- Keep title with user name in AuthorPresentationEditor form
- Fix duplicate display issue

hooks/useNostrAuth.ts

@@ -46,4 +46,3 @@ export function useNostrAuth() {
     disconnect,
   }
 }
-

lib/nostrAuth.ts

@@ -141,4 +141,3 @@ export class NostrAuthService {
 }
 
 export const nostrAuthService = new NostrAuthService()
-

pages/presentation.tsx

@@ -43,13 +43,6 @@ function PresentationLayout() {
       <main className="min-h-screen bg-cyber-darker">
         <PageHeader />
         <div className="max-w-4xl mx-auto px-4 py-8">
-          <div className="mb-6">
-            <h2 className="text-3xl font-bold text-neon-cyan font-mono mb-2">{t('presentation.title')}</h2>
-            <p className="text-cyber-accent mt-2">
-              {t('presentation.description')}
-            </p>
-          </div>
-
           <AuthorPresentationEditor />
         </div>
         <Footer />