feat(entity): 添加首页优势模块配置字段

- 在 CmsWebsiteSetting 实体中新增 features 字段
- features 字段用于存储首页优势模块配置信息，格式为 JSON
- 添加了对应的 Schema 注解及描述说明

src/main/java/com/gxwebsoft/cms/entity/CmsWebsiteSetting.java

@@ -68,6 +68,9 @@ public class CmsWebsiteSetting implements Serializable {
     @Schema(description = "导航栏最多显示数量")
     private Boolean maxMenuNum;
 
+    @Schema(description = "首页优势模块配置(JSON)")
+    private String features;
+
     @Schema(description = "排序号")
     private Integer sortNumber;