Refactor container layout and remove redundant wrappers

Reorganized container layouts across dashboard and event pages to remove redundant `div` wrappers and ensure consistent structure. This improves maintainability and simplifies the codebase while retaining visual behavior.

frontend/src/app/(main)/dashboard/events/new/page.tsx

@@ -81,7 +81,6 @@ export default function CreateEventPage() {
 
   return (
     <>
-      <div className="container mx-auto px-4 py-12 max-w-4xl">
       <Card className="shadow-lg">
         <CardHeader>
           <CardTitle className="text-2xl">Create New Event</CardTitle>
@@ -214,7 +213,6 @@ export default function CreateEventPage() {
           </form>
         </CardContent>
       </Card>
-      </div>
     </>
   );
 }

frontend/src/app/(main)/dashboard/layout.tsx

@@ -41,7 +41,7 @@ export default function MainLayout({
   return (
     <>
       <Navbar />
-      {children}
+      <div className="container mx-auto px-4 py-12">{children}</div>
     </>
   );
 }

frontend/src/app/(main)/dashboard/page.tsx

@@ -25,7 +25,6 @@ export default function DashboardPage() {
 
   return (
     <>
-      <div className="container mx-auto px-4 py-12">
       <div className="max-w-7xl mx-auto">
         <h1 className="text-3xl font-bold mb-8">Dashboard</h1>
 
@@ -108,7 +107,6 @@ export default function DashboardPage() {
             </div>
           )}
       </div>
-      </div>
     </>
   );
 }