refactor: improve filtering of hidden posts in PostsController

- Refactored the code in `PostsController.php` to filter out hidden posts before sorting by date for better performance and accuracy.
- Updated the blade template `listposts.blade.php` to adjust formatting and structure for displaying posts.

app/Http/Controllers/PostsController.php

@@ -10,7 +10,9 @@ class PostsController extends Controller
 {
     public function index()
     {
-        $posts = Sheets::all()->sortByDesc('date');
+        $posts = Sheets::all()->filter(function ($post) {
+            return !$post->hidden;
+        })->sortByDesc('date');
         $paginatedPosts = Paginate::collection($posts, 6);
 
         return view('posts.index', [