fix: move thinkingConfig to root level of Gemini request body

thinkingConfig must be a top-level key in the request, NOT nested inside
generationConfig. This is required for gemini-2.5-flash and newer models.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Http/Livewire/Chat/ShowConfiguracionChat.php

@@ -107,10 +107,10 @@ class ShowConfiguracionChat extends Component
                 ->withHeaders(['Content-Type' => 'application/json'])
                 ->post("{$url}?key={$key}", [
                     'contents'         => [['parts' => [['text' => 'Responde solo "ok"']]]],
-                    'generationConfig' => array_merge(
-                        ['maxOutputTokens' => 5, 'temperature' => 0],
-                        preg_match('/gemini-(2\.5|3[\.\d]*)/', $model) ? ['thinkingConfig' => ['thinkingBudget' => 0]] : []
-                    ),
+                    'generationConfig' => ['maxOutputTokens' => 5, 'temperature' => 0],
+                    ...(preg_match('/gemini-(2\.5|3[\.\d]*)/', $model)
+                        ? ['thinkingConfig' => ['thinkingBudget' => 0]]
+                        : []),
                 ]);
 
             $ms   = (int) ((microtime(true) - $inicio) * 1000);