feat(hackathon): Update UI landing page, dashboard, onboarding (#62)

* feat: update landing page

* feat: Add favicon and SEO (JSON-LD schema, meta tags)

- Add favicon image
- Add JSON-LD schema for Hackathon event
- Add react-helmet-async for managing meta tags

* chore: remove react-helmet-async

* chore: update landing page

* chore: update UI for signup and login

- add back button for better UX

* feat: add image loading state and skeleton UI for team dashboard

* fix: landing navbar not sticky to top, fix onboarding UI

* feat(hackathon): update UI

- Update dashboard, onboarding user, edit profile, and team layout
  to make it more consistent

* fix: optimize placeholder banner image & minor fix dark mode

---------

Co-authored-by: Maulana Sodiqin <sodiqincahyana1@gmail.com>
Co-authored-by: Muhammad Zakir Ramadhan <61570975+zakirkun@users.noreply.github.com>

apps/hackathon/src/app/teams/layout.tsx

@@ -9,21 +9,35 @@ const TeamsLayout: FC = (): ReactElement => {
     <div className="flex min-h-screen bg-gray-50 dark:bg-neutral-950">
       <Sidebar isOpen={sidebarOpen} onClose={() => setSidebarOpen(false)} />
 
-      <div className="flex-1 flex flex-col overflow-auto">
+      <div className="flex-1 flex flex-col">
         {/* Mobile Header with Hamburger */}
-        <div className="lg:hidden bg-white dark:bg-neutral-900 border-b dark:border-neutral-700 px-4 py-3 flex items-center">
-          <button
-            onClick={() => setSidebarOpen(true)}
-            className="p-2 rounded-lg hover:bg-gray-100 dark:hover:bg-neutral-800 transition-colors"
-          >
-            <svg className="w-6 h-6 text-gray-600 dark:text-neutral-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 6h16M4 12h16M4 18h16" />
-            </svg>
-          </button>
-          <h1 className="ml-3 text-lg font-bold text-gray-900 dark:text-white">Hackathon</h1>
+        <div className="lg:hidden sticky top-0 bg-white dark:bg-neutral-900 border-b dark:border-neutral-700 px-4 py-3 z-10">
+          <div className="flex items-center">
+            <button
+              onClick={() => setSidebarOpen(true)}
+              className="p-2 rounded-lg hover:bg-gray-100 dark:hover:bg-neutral-800 transition-colors"
+            >
+              <svg
+                className="w-6 h-6 text-gray-600 dark:text-neutral-400"
+                fill="none"
+                stroke="currentColor"
+                viewBox="0 0 24 24"
+              >
+                <path
+                  strokeLinecap="round"
+                  strokeLinejoin="round"
+                  strokeWidth={2}
+                  d="M4 6h16M4 12h16M4 18h16"
+                />
+              </svg>
+            </button>
+            <h1 className="ml-3 text-lg font-bold text-gray-900 dark:text-white">
+              Hackathon
+            </h1>
+          </div>
         </div>
 
-        <main className="flex-1 overflow-auto">
+        <main className="flex-1">
           <Outlet />
         </main>
       </div>