fix abstract chat history test

Author: ilvalerione

src/Chat/History/AbstractChatHistory.php

@@ -218,8 +218,7 @@ protected function ensureStartsWithUser(): void
 
             if (\in_array($role, [
                 MessageRole::USER->value,
-                MessageRole::ASSISTANT->value,
-                MessageRole::MODEL->value,
+                MessageRole::DEVELOPER->value,
             ], true)) {
                 $firstIndex = $index;
                 break;

tests/ChatHistory/DummyTokenCounter.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace NeuronAI\Tests\ChatHistory;
 
 use NeuronAI\Chat\History\TokenCounterInterface;