refactor: 계획에서 나가거나 추방될 경우 DB에서 바로 삭제

Author: kms152000

src/main/java/com/back/web7_9_codecrete_be/domain/plans/entity/Plan.java

@@ -92,6 +92,11 @@ public void addParticipant(PlanParticipant participant) {
         participant.setPlan(this);
     }
 
+    public void removeParticipant(PlanParticipant participant) {
+        this.participants.remove(participant);
+        participant.setPlan(null);
+    }
+
     public void addSchedule(Schedule schedule) {
         this.schedules.add(schedule);
         schedule.setPlan(this);

src/main/java/com/back/web7_9_codecrete_be/domain/plans/service/PlanService.java

@@ -1091,8 +1091,9 @@ public void kickParticipant(Long planId, Long participantId, User user) {
             throw new BusinessException(PlanErrorCode.CANNOT_REMOVE_OWNER);
         }
 
-        // 상태를 REMOVED로 변경
-        participant.updateInviteStatus(PlanParticipant.InviteStatus.REMOVED);
+        // 참가자 삭제 (Plan의 participants 리스트에서도 제거)
+        plan.removeParticipant(participant);
+        planParticipantRepository.delete(participant);
     }
 
     /**
@@ -1119,9 +1120,9 @@ public void quitPlan(Long planId, User user) {
                     .findByUser_IdAndPlan_PlanId(user.getId(), planId)
                     .orElseThrow(() -> new BusinessException(PlanErrorCode.PARTICIPANT_NOT_FOUND));
 
-            // 상태를 LEFT로 변경
-            participant.updateInviteStatus(PlanParticipant.InviteStatus.LEFT);
-            planParticipantRepository.save(participant);
+            // 참가자 삭제 (Plan의 participants 리스트에서도 제거)
+            plan.removeParticipant(participant);
+            planParticipantRepository.delete(participant);
             // 명시적으로 flush하여 OptimisticLockException을 즉시 감지
             planParticipantRepository.flush();
         } catch (OptimisticLockException e) {