feat: add support for gpt-5 models and adjust temperature settings

- Updated the model list to include various gpt-5 variants.
- Enhanced the ConvertOpenAIRequest function to handle gpt-5 model temperature settings based on specific model prefixes.
- Adjusted default cache and model ratios for new gpt-5 models.

relay/channel/openai/adaptor.go

@@ -206,12 +206,21 @@ func (a *Adaptor) ConvertOpenAIRequest(c *gin.Context, info *relaycommon.RelayIn
 			}
 		}
 	}
-	if strings.HasPrefix(request.Model, "o") {
+	if strings.HasPrefix(request.Model, "o") || strings.HasPrefix(request.Model, "gpt-5") {
 		if request.MaxCompletionTokens == 0 && request.MaxTokens != 0 {
 			request.MaxCompletionTokens = request.MaxTokens
 			request.MaxTokens = 0
 		}
-		request.Temperature = nil
+
+		if strings.HasPrefix(request.Model, "o") {
+			request.Temperature = nil
+		}
+
+		if strings.HasPrefix(request.Model, "gpt-5") {
+			if request.Model != "gpt-5-chat-latest" {
+				request.Temperature = nil
+			}
+		}
 
 		// 转换模型推理力度后缀
 		effort, originModel := parseReasoningEffortFromModelSuffix(request.Model)

relay/channel/openai/constant.go

@@ -18,6 +18,9 @@ var ModelList = []string{
 	"o3-mini-high", "o3-mini-2025-01-31-high",
 	"o3-mini-low", "o3-mini-2025-01-31-low",
 	"o3-mini-medium", "o3-mini-2025-01-31-medium",
+	"gpt-5", "gpt-5-2025-08-07", "gpt-5-chat-latest",
+	"gpt-5-mini", "gpt-5-mini-2025-08-07",
+	"gpt-5-nano", "gpt-5-nano-2025-08-07",
 	"o1", "o1-2024-12-17",
 	"gpt-4o-audio-preview", "gpt-4o-audio-preview-2024-10-01",
 	"gpt-4o-realtime-preview", "gpt-4o-realtime-preview-2024-10-01", "gpt-4o-realtime-preview-2024-12-17",