Storage Migration, Build Fixes, and Documentation Improvements

- Storage migration to SAF, removal of old permissions
- APK/AAB signing fixes, improved R8/ProGuard rules
- Added GPLv3 license and bug/feature reporting templates
- Integrated Fastlane for automated builds and releases
- Optimized code, notifications and progress reminders
- Direct links for easier access to apps
- Fixed Excel compatibility issues in older versions
