feat(复习)：回忆对比优先走 AI 语义对比，失败时降级为内置算法

- CompareResult.java：新增 evaluation 字段（AI 对比时写入评价文本）
- AiServiceClient.java：新增 compareRecall()，调用 lpt-ai /ai/compare-recall
- StandardMindMapServiceImpl.java：recallCompare() 中注入 AiServiceClient，
  优先 try AI 语义对比，含层级上下文和同义表达识别；
  AI 不可用或失败时自动 fallback 到内置标题匹配算法
- StandardMindMapServiceImplTest.java：适配新增的 AiServiceClient 依赖

src/main/java/com/guo/learningprogresstracker/service/impl/StandardMindMapServiceImpl.java

@@ -39,6 +39,7 @@ public class StandardMindMapServiceImpl implements StandardMindMapService {
 
     private final List<MindMapAiClient> aiClients;
     private final ObjectMapper objectMapper;
+    private final AiServiceClient aiServiceClient;
 
     private static final String GENERATOR_BUILTIN = "BUILTIN";
     private static final String GENERATOR_USER = "USER";
@@ -105,8 +106,28 @@ public class StandardMindMapServiceImpl implements StandardMindMapService {
         MindMapNode standardRoot = MindMapTreeTool.fromJson(standard.getContent(), objectMapper);
         MindMapNode recallRoot = MindMapTreeTool.parseOutline(recallOutline);
 
-        // 3. 执行对比
-        CompareResult result = compareTrees(standardRoot, recallRoot);
+        // 3. 执行对比（优先 AI 语义对比，失败时降级为内置算法）
+        CompareResult result;
+        if (aiServiceClient.isConfigured()) {
+            String taskName = tasksMapper.selectOne(
+                    Wrappers.<TaskEntity>lambdaQuery().eq(TaskEntity::getTaskNum, taskNum).last("LIMIT 1"))
+                    .getTaskName();
+            var optResult = aiServiceClient.compareRecall(
+                    taskName,
+                    MindMapTreeTool.toFullOutline(standardRoot),
+                    recallOutline
+            );
+            if (optResult.isPresent()) {
+                result = optResult.get();
+                log.info("AI 回忆对比: taskNum={}, recallRatio={}, evaluation={}",
+                        taskNum, result.getRecallRatio(),
+                        result.getEvaluation() != null ? result.getEvaluation().substring(0, Math.min(50, result.getEvaluation().length())) : "");
+            } else {
+                result = compareTrees(standardRoot, recallRoot);
+            }
+        } else {
+            result = compareTrees(standardRoot, recallRoot);
+        }
 
         // 4. 序列化对比结果
         String resultJson;