Adding a self test to check that web workers are supported

src/workers/dispatcher-worker.ts

@@ -27,7 +27,6 @@ import { deleteTrk, getTrk, putNewTrk } from '../db/trk';
 import { putTrkpt } from '../db/trkpt';
 import { getTrkseg, appendTrkpt } from '../db/trkseg';
 import { getWpt, putWpt, deleteWpt } from '../db/wpt';
-import { until } from '../lib/async-wait';
 
 //const self = globalThis as unknown as WorkerGlobalScope;
 
@@ -75,6 +74,8 @@ onmessage = async function (e) {
     putAccount,
     getCurrentAccount,
     putCurrentAccount,
+
+    ping: (params: any) => `${params.what} pong`,
   };
 
   //  console.log({ caller: 'dispatcher-worker / onmessage', e });