refactor(main): modernize DOM update flow with async/await

[KristjanESPERANTO]

Follow-up to #4185. This PR replaces .then()/.catch() chains in the DOM update flow with async/await, making the code easier to read and reason about.

What changed:

• createDomObjects and MM.updateDom are now async, the nested .then() callbacks are gone
• Extracted a small createModuleDom() helper to keep the loop in createDomObjects readable
• Errors in createDomObjects are caught in a single try/catch - before, a failing module could cause an unhandled Promise rejection
• updateDomWithContent now properly awaits the full show animation before resolving. The old code called resolve() while the animation was still running, which was technically wrong
• Fixed @param {Promise} callback in JSDoc - it's not a Promise, it's a plain () => void function