fix: 收窄 OpenAI o 系列模型适配范围 (#5293)

* fix: 收窄 OpenAI o 系列模型适配范围

* fix(openai): 限制 gpt-5 适配仅作用于 OpenAI 模型

* fix(openai): narrow o-series reasoning model detection

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Co-authored-by: Seefs <i@seefs.me>

controller/channel-test.go

@@ -814,7 +814,7 @@ func buildTestRequest(model string, endpointType string, channel *model.Channel,
 		testRequest.StreamOptions = &dto.StreamOptions{IncludeUsage: true}
 	}
 
-	if strings.HasPrefix(model, "o") {
+	if dto.IsOpenAIReasoningOModel(model) {
 		testRequest.MaxCompletionTokens = lo.ToPtr(uint(16))
 	} else if strings.Contains(model, "thinking") {
 		if !strings.Contains(model, "claude") {