Move all user-facing strings into res/values/strings.xml (English base) and
add res/values-nl/strings.xml (Dutch). Composables use stringResource;
coroutine-set and non-composable strings (ViewModel, PaperlessClient) resolve
via Context.getString. Mark app_name translatable=false. Bump to 0.3.0.
Fixes#5
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
