feat: 任务开始页面，相关逻辑补充

src/main/java/com/guo/learningprogresstracker/service/StudySessionsService.java

@@ -5,6 +5,7 @@ import com.guo.learningprogresstracker.entity.StudySessionsEntity;
 import com.baomidou.mybatisplus.extension.service.IService;
 import com.guo.learningprogresstracker.exception.ErrorParameterException;
 
+import java.time.LocalDateTime;
 import java.util.ArrayList;
 
 /**
@@ -20,5 +21,7 @@ public interface StudySessionsService extends IService<StudySessionsEntity> {
 
     void endedStudySession(String sessionNum, String content) throws ErrorParameterException;
 
-    void pauseStudySession(String sessionNum) throws ErrorParameterException;
+    void pauseStudySession(String sessionNum, LocalDateTime endTime) throws ErrorParameterException;
+
+    void continueStudySession(String sessionNum) throws ErrorParameterException;
 }