Update default initial cards count in KanbanBoard to improve user experience

Author: ManukMinasyan

src/Livewire/KanbanBoard.php

@@ -98,7 +98,7 @@ public function mount(
         $this->searchable = $searchable;
 
         // Set default limits
-        $initialCardsCount = $initialCardsCount ?? 50;
+        $initialCardsCount = $initialCardsCount ?? 15;
         $this->cardsIncrement = $cardsIncrement ?? 10;
 
         // Initialize columns using adapter config