feat: 预设提示词的对话调用

backend/internal/llm/client.go

@@ -44,5 +44,27 @@ func (c *Client) Chat(ctx context.Context, messages []llms.MessageContent) (stri
     }
     log.Printf("[INFO] Chat completed successfully, choice length: %d", len(resp.Choices[0].Content))
 
+	return resp.Choices[0].Content, nil
+}
+
+// Client包含系统提示词的调用
+func (c *Client) ChatWithSystemPrompt(ctx context.Context, systemPrompt string, messages []llms.MessageContent) (string, error) {
+	// 构造系统提示词消息
+	systemMessage := llms.TextParts(llms.ChatMessageTypeSystem, systemPrompt)
+	
+	// 将系统提示词插入到消息列表头部
+	allMessages := append([]llms.MessageContent{systemMessage}, messages...)
+
+	resp, err := c.llm.GenerateContent(ctx, allMessages)
+	if err != nil {
+		log.Printf("[ERROR] GenerateContent with system prompt failed: %v", err)
+		return "", fmt.Errorf("generate content error: %w", err)
+	}
+	if resp == nil || len(resp.Choices) == 0 {
+		log.Printf("[WARN] Response with system prompt is empty or has no choices")
+		return "", fmt.Errorf("no content choices returned")
+	}
+	log.Printf("[INFO] Chat with system prompt completed successfully, choice length: %d", len(resp.Choices[0].Content))
+
 	return resp.Choices[0].Content, nil
 }