app: getAppModule should source module info from backend instead of hardcoding

In `packages/modules/app/src/app/App.ts`, there's a TODO noting a value should come from the backend rather than being derived/hardcoded client-side:

```ts
// TODO - this should come from backend
```

Update the API/manifest to surface this value and consume it here instead.

Start in packages/modules/app/src/app/App.ts and inspect the TODO and the value currently derived or hardcoded there. Trace the related API or manifest definitions to determine where module information is exposed. Done means the value is surfaced by the backend API or manifest and consumed by App.ts instead of being derived client-side.

Written by the indexing model from the issue text.