refactor(headers): streamline User-Agent handling and introduce GeminiCLI versioning

internal/translator/codex/openai/responses/codex_openai-responses_request_test.go

@@ -264,18 +264,18 @@ func TestConvertSystemRoleToDeveloper_AssistantRole(t *testing.T) {
 	}
 }
 
-func TestUserFieldDeletion(t *testing.T) {  
+func TestUserFieldDeletion(t *testing.T) {
 	inputJSON := []byte(`{  
 		"model": "gpt-5.2",  
 		"user": "test-user",  
 		"input": [{"role": "user", "content": "Hello"}]  
-	}`)  
-	  
-	output := ConvertOpenAIResponsesRequestToCodex("gpt-5.2", inputJSON, false)  
-	outputStr := string(output)  
-	  
-	// Verify user field is deleted  
-	userField := gjson.Get(outputStr, "user")  
+	}`)
+
+	output := ConvertOpenAIResponsesRequestToCodex("gpt-5.2", inputJSON, false)
+	outputStr := string(output)
+
+	// Verify user field is deleted
+	userField := gjson.Get(outputStr, "user")
 	if userField.Exists() {
 		t.Errorf("user field should be deleted, but it was found with value: %s", userField.Raw)
 	}