fix: recalculate timers

- recalculate timers in same update call if necessary
- use new variable to keep track of upcoming rolling events without recalculating titles

server/src/classes/Timer.js

@@ -12,6 +12,7 @@ export class Timer {
   current = null;
   timeTag = null;
   secondaryTimer = null;
+  _secondaryTarget = null;
   _finishAt = null;
   _finishedAt = null;
   _startedAt = null;
@@ -122,6 +123,7 @@ export class Timer {
     this.current = this.duration;
     this.running = null;
     this.secondaryTimer = null;
+    this._secondaryTarget = null;
     this._finishAt = null;
     this._finishedAt = null;
     this._startedAt = null;