fix(news): drop unsupported temperature from summarize (gpt-5.x 400)

The /news article summarize call sent temperature: 0.3, which gpt-5.x reasoning
models reject ('Only the default (1) value is supported') -> 400. Remove it, same
as the finance report fix. Update the test to assert no temperature is sent.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ralyodio

src/app/api/news/summarize/route.test.ts

@@ -473,12 +473,13 @@ describe('News Summarize API Route', () => {
           response_format: { type: 'json_object' },
           max_completion_tokens: 1500,
           reasoning_effort: 'high',
-          temperature: 0.3,
         }),
         expect.objectContaining({
           timeout: 60000,
         })
       );
+      // gpt-5.x reasoning models reject a custom temperature; we must not send one.
+      expect(mockOpenAICreate.mock.calls[0][0]).not.toHaveProperty('temperature');
     });
 
     it('should include article content in the prompt', async () => {

src/app/api/news/summarize/route.ts

@@ -195,7 +195,8 @@ ${truncatedContent}`;
         response_format: { type: 'json_object' },
         max_completion_tokens: 1500,
         reasoning_effort: 'high',
-        temperature: 0.3,
+        // gpt-5.x reasoning models only support the default temperature (1);
+        // passing a custom value returns a 400.
       },
       {
         timeout: 60000, // 60 second timeout