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/Services/GeminiIntentService.php

@@ -21,14 +21,17 @@ class GeminiIntentService
         $this->apiUrl = "https://generativelanguage.googleapis.com/v1beta/models/{$this->model}:generateContent";
     }
 
-    private function generationConfig(array $extra = []): array
+    private function buildRequest(array $contents, array $genConfig = []): array
     {
-        $config = array_merge(['temperature' => 0.1, 'maxOutputTokens' => 100], $extra);
-        // 2.5+ models require thinkingConfig to avoid response format issues
+        $body = [
+            'contents'         => $contents,
+            'generationConfig' => array_merge(['temperature' => 0.1, 'maxOutputTokens' => 100], $genConfig),
+        ];
+        // thinkingConfig goes at root level (NOT inside generationConfig) for 2.5+ models
         if (preg_match('/gemini-(2\.5|3[\.\d]*)/', $this->model)) {
-            $config['thinkingConfig'] = ['thinkingBudget' => 0];
+            $body['thinkingConfig'] = ['thinkingBudget' => 0];
         }
-        return $config;
+        return $body;
     }
 
     /**
@@ -47,10 +50,9 @@ class GeminiIntentService
         try {
             $response = Http::withHeaders(['Content-Type' => 'application/json'])
                 ->timeout(8)
-                ->post("{$this->apiUrl}?key={$this->apiKey}", [
-                    'contents' => [['parts' => [['text' => $prompt]]]],
-                    'generationConfig' => $this->generationConfig(),
-                ]);
+                ->post("{$this->apiUrl}?key={$this->apiKey}",
+                    $this->buildRequest([['parts' => [['text' => $prompt]]]])
+                );
 
             $tiempoMs = (int) ((microtime(true) - $inicio) * 1000);