Use alarms to feed stats

[whoabuddy]

We can have alarms that run on an interval and update internal application stats.

Example alarm:

async alarm(): Promise<void> {
  try {
    console.log(`ContextDO: alarm activated`);
  } catch (error) {
    console.error(`ContextDO: alarm execution failed: ${error instanceof Error ? error.message : tring(error)}`);
  } finally {
    // Always schedule next alarm if one isn't set
    const currentAlarm = await this.ctx.storage.getAlarm();
    if (currentAlarm === null) {
      this.ctx.storage.setAlarm(Date.now() + this.ALARM_INTERVAL_MS);
    }
  }
}