Add set/get/clear store registry URL method channel handlers on Android,
iOS, and Go backend so users can configure a custom extension repository.
Store tab now shows a setup screen when no registry URL is configured,
with a cleaner layout (removed redundant description and helper text)
and visible TextField borders for dark theme.
Minor comment and formatting cleanups across several files.
- Add PopScope with canPop:true to all settings pages for predictive back gesture support
- Change settings navigation to use PageRouteBuilder instead of MaterialPageRoute
- Add album folder structure setting (artist_album vs album_only)
- Fix extension search result parsing to handle both array and object formats
- Update CHANGELOG
Fixes back gesture freeze issue on OnePlus and other Android 13+ devices with gesture navigation
zarzet