Fix scheduling errors

backend/app/Jobs/PublishNextArticleJob.php

@@ -32,9 +32,8 @@ public function handle(): void
     {
         // Get the oldest approved article that hasn't been published yet
         $article = Article::where('approval_status', 'approved')
-            ->whereNotNull('validated_at')
             ->whereDoesntHave('articlePublication')
-            ->oldest('validated_at')
+            ->oldest('created_at')
             ->first();
 
         if (! $article) {
@@ -45,7 +44,7 @@ public function handle(): void
             'article_id' => $article->id,
             'title' => $article->title,
             'url' => $article->url,
-            'validated_at' => $article->validated_at
+            'created_at' => $article->created_at
         ]);
 
         // Fetch article data