MediaWiki Extension with Webpack and TypeScript fails to load mw (mw.util)

Question

I'm not a frontend developer. Until a few days ago I haven't tried npm, webpack and typescript. But now (somehow) everything builds (you can find the code here).

But when I upload the extension (before the migration to TS it worked) and try to use it in MediaWiki I get an annoying message (annoying because I've spent a couple of weeks fighting in this world)

app.ts:378 Uncaught ReferenceError: mw is not defined
    at MyClass.loadWikiArticlesAjax (app.ts:378:18)
    at MyClass.initialize (app.ts:22:17)
    at new MyClass (app.ts:18:17)
    at ./includes/js/app.ts (app.ts:445:1)
    at __webpack_require__ (bootstrap:19:1)
    at startup:4:1
    at startup:4:1
loadWikiArticlesAjax @ app.ts:378
initialize @ app.ts:22
MyClass @ app.ts:18
./includes/js/app.ts @ app.ts:445
__webpack_require__ @ bootstrap:19
(anonymous) @ startup:4
(anonymous) @ startup:4
app.ts:391 Uncaught TypeError: Cannot read properties of undefined (reading 'query')
    at Object.success (app.ts:391:47)
    at fire (jquery.js?7e265:3500:31)
    at Object.fireWith [as resolveWith] (jquery.js?7e265:3630:7)
    at done (jquery.js?7e265:9822:14)
    at XMLHttpRequest.<anonymous> (jquery.js?7e265:10083:9)

Any hint?