refactor(puzzle): 重构元素DTO及新增元素基类

- 将ElementCreateRequest和PuzzleElementDTO中的elementType从Integer改为String
- 删除所有类型特定字段，新增config和configMap支持JSON配置
- 新增BaseElement抽象基类定义元素通用行为
- 添加ElementConfig接口和具体实现类ImageConfig、TextConfig
- 创建ElementFactory工厂类和ElementRegistrar注册器
- 新增ElementType枚举和ElementValidationException异常类
- 实现ImageElement和TextElement具体元素类
- 添加Position位置信息封装类

src/main/java/com/ycwl/basic/puzzle/element/renderer/RenderContext.java

@@ -0,0 +1,74 @@
+package com.ycwl.basic.puzzle.element.renderer;
+
+import lombok.Data;
+
+import java.awt.*;
+import java.util.Map;
+
+/**
+ * 渲染上下文
+ * 封装渲染时需要的所有上下文信息
+ *
+ * @author Claude
+ * @since 2025-01-18
+ */
+@Data
+public class RenderContext {
+
+    /**
+     * 图形上下文
+     */
+    private Graphics2D graphics;
+
+    /**
+     * 动态数据（key=elementKey, value=实际值）
+     */
+    private Map<String, String> dynamicData;
+
+    /**
+     * 画布宽度
+     */
+    private Integer canvasWidth;
+
+    /**
+     * 画布高度
+     */
+    private Integer canvasHeight;
+
+    /**
+     * 是否启用抗锯齿
+     */
+    private boolean antiAliasing = true;
+
+    /**
+     * 是否启用高质量渲染
+     */
+    private boolean highQuality = true;
+
+    public RenderContext(Graphics2D graphics, Map<String, String> dynamicData) {
+        this.graphics = graphics;
+        this.dynamicData = dynamicData;
+    }
+
+    public RenderContext(Graphics2D graphics, Map<String, String> dynamicData,
+                        Integer canvasWidth, Integer canvasHeight) {
+        this.graphics = graphics;
+        this.dynamicData = dynamicData;
+        this.canvasWidth = canvasWidth;
+        this.canvasHeight = canvasHeight;
+    }
+
+    /**
+     * 获取动态数据（带默认值）
+     *
+     * @param key          数据key
+     * @param defaultValue 默认值
+     * @return 数据值
+     */
+    public String getDynamicData(String key, String defaultValue) {
+        if (dynamicData == null) {
+            return defaultValue;
+        }
+        return dynamicData.getOrDefault(key, defaultValue);
+    }
+}