feat: 学习材料地址（materialUrl）支持

- TaskInfo DTO 新增 materialUrl 字段
- StudySessionResponse 新增 materialUrl 和 taskId 字段
- StudySessionsServiceImpl 在学习会话响应中填充 materialUrl 和 taskId
- TasksServiceImpl 更新任务时保留原有 taskNum
- 修复 TaskInfoResponse 注释格式错误

src/main/java/com/guo/learningprogresstracker/dto/TaskInfo.java

@@ -13,6 +13,8 @@ public class TaskInfo {
     private String taskName;
     // 任务描述
     private String taskDescription;
+    // 学习材料地址
+    private String materialUrl;
     // 任务优先级
     private Double taskPriority;
     // 上次该任务学习情况

src/main/java/com/guo/learningprogresstracker/dto/response/StudySessionResponse.java

@@ -17,6 +17,12 @@ public class StudySessionResponse {
     @Schema(description = "任务编号")
     private String taskNum;
 
+    @Schema(description = "学习材料（Markdown）")
+    private String materialUrl;
+
+    @Schema(description = "任务ID")
+    private Integer taskId;
+
     @Schema(description = "学习开始时间")
     private LocalDateTime startTime;
 

src/main/java/com/guo/learningprogresstracker/dto/response/TaskInfoResponse.java

@@ -21,6 +21,7 @@ public class TaskInfoResponse {
      */
     private String materialUrl;
 
+    /**
     /**
      * 用户设置的任务紧急性
      */

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

@@ -73,6 +73,8 @@ public class StudySessionsServiceImpl extends ServiceImpl<StudySessionsMapper, S
 
         StudySessionResponse response = StudySessionConvert.MAPPER.toStudySessionResponse(session);
         response.setTaskName(taskEntity.getTaskName());
+        response.setMaterialUrl(taskEntity.getMaterialUrl());
+        response.setTaskId(taskEntity.getId());
 
         if (session.isOverTime()) {
             response.setSystemMessage("上段学习任务已经超时25分钟，将仅计算为25分钟的有效学习时间，请注意休息！");

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

@@ -90,6 +90,7 @@ public class TasksServiceImpl extends ServiceImpl<TasksMapper, TaskEntity>
             throw new IllegalArgumentException("任务ID格式错误: " + taskId);
         }
         taskEntity.setId(id);
+        taskEntity.setTaskNum(existingTask.getTaskNum());
         // 维度数据可能变化，更新时重算优先级
         PriorityDto priorityDto = RequestConvert.MAPPER.taskRequestToPriorityDto(updatedTask);
         taskEntity.setCalculatedPriority(CalculatedPriorityTool.calculatedPriority(priorityDto, priorityWeightsService.getWeights()));