feat: implement Play Store search paging

- Add `PlayStorePagingSource` and `PlayStorePagingRepository` to handle infinite scrolling for Standard Apps
- Integrate Play Store paging flow into `SearchViewModelV2` and `SearchResultsContent`
- Create `PagingPlayStoreResultList` composable for displaying Play Store items
- Centralize icon URL generation in `Application` model and refactor adapters to use it
- Introduce `searchVersion` to properly reset scroll state on new search queries