更新pom.xml以添加reactor-netty-http依赖，修改ChatApplication以启用LlmApiProperties配置，优化ChatServiceImpl以处理LLM服务的JSON响应，添加内容提取和清理方法，更新application.yml以配置LLM服务的基本URL和日志级别。

src/main/java/com/yundage/chat/config/LlmApiProperties.java

@@ -0,0 +1,28 @@
+package com.yundage.chat.config;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * LLM API配置属性类
+ */
+@ConfigurationProperties(prefix = "llm")
+public class LlmApiProperties {
+    private String baseUrl;
+    private String apiKey;  // 可选，预留未来认证使用
+
+    public String getBaseUrl() {
+        return baseUrl;
+    }
+
+    public void setBaseUrl(String baseUrl) {
+        this.baseUrl = baseUrl;
+    }
+
+    public String getApiKey() {
+        return apiKey;
+    }
+
+    public void setApiKey(String apiKey) {
+        this.apiKey = apiKey;
+    }
+}