feat(gemini): map OpenAI stop to Gemini stopSequences

relay/channel/gemini/relay-gemini.go

@@ -217,6 +217,13 @@ func CovertOpenAI2Gemini(c *gin.Context, textRequest dto.GeneralOpenAIRequest, i
 			"IMAGE",
 		}
 	}
+	if stopSequences := parseStopSequences(textRequest.Stop); len(stopSequences) > 0 {
+		// Gemini supports up to 5 stop sequences
+		if len(stopSequences) > 5 {
+			stopSequences = stopSequences[:5]
+		}
+		geminiRequest.GenerationConfig.StopSequences = stopSequences
+	}
 
 	adaptorWithExtraBody := false
 
@@ -631,6 +638,31 @@ func CovertOpenAI2Gemini(c *gin.Context, textRequest dto.GeneralOpenAIRequest, i
 	return &geminiRequest, nil
 }
 
+// parseStopSequences 解析停止序列，支持字符串或字符串数组
+func parseStopSequences(stop any) []string {
+	if stop == nil {
+		return nil
+	}
+
+	switch v := stop.(type) {
+	case string:
+		if v != "" {
+			return []string{v}
+		}
+	case []string:
+		return v
+	case []interface{}:
+		sequences := make([]string, 0, len(v))
+		for _, item := range v {
+			if str, ok := item.(string); ok && str != "" {
+				sequences = append(sequences, str)
+			}
+		}
+		return sequences
+	}
+	return nil
+}
+
 func hasFunctionCallContent(call *dto.FunctionCall) bool {
 	if call == nil {
 		return false