feat: 添加定时系统

- 实现定时任务

internal/ckwk/session_manager.go

@@ -115,3 +115,44 @@ func (m *SessionManager) KeepAlive(ctx context.Context, id string, wk *WK) {
 		}
 	}
 }
+
+func (m *SessionManager) ClearAll() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	for sessionID, item := range m.sessions {
+		// 停止 KeepAlive
+		if item.cancel != nil {
+			item.cancel()
+		}
+
+		userKey := item.Instance.Host + ":" + item.Instance.Username
+		delete(m.userToSession, userKey)
+		delete(m.sessions, sessionID)
+
+		log.Info("清理 Session", zap.String("id", sessionID))
+	}
+
+	log.Info("所有 Session 已清空")
+}
+
+func (m *SessionManager) ClearExpired(d time.Duration) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	now := time.Now()
+
+	for sessionID, item := range m.sessions {
+		if now.Sub(item.LastValue) > d {
+			if item.cancel != nil {
+				item.cancel()
+			}
+
+			userKey := item.Instance.Host + ":" + item.Instance.Username
+			delete(m.userToSession, userKey)
+			delete(m.sessions, sessionID)
+
+			log.Info("清理过期 Session", zap.String("id", sessionID))
+		}
+	}
+}