Fix Android re-auth by adding SecureStore backup exclusion rules
expo-secure-store config plugin adds manifest references to backup rules
but doesn't create the actual XML files. This causes Android to backup
encrypted tokens without the KeyStore encryption keys, making restored
tokens undecryptable and forcing users to re-authenticate.
Added custom plugin that generates the missing XML files:
- secure_store_backup_rules.xml (Android <= 11)
- secure_store_data_extraction_rules.xml (Android 12+)
Fixes repeated logout issue reported on Android 16 (Pixel Pro 9).