Authenticator and sync hardening update.
- Unified authenticator to canonical handling and removed legacy TOTP paths.
- Added Authenticator search and Import/Export menu (QR + clipboard import, clipboard export).
- Simplified main Files FAB import options by removing redundant file-import actions.
- Fixed Authenticator FAB overlap issue.
- Improved authenticator access controls and lockout behavior.
- Cloud Sync reliability improvements, plus performance/UI polish and bug fixes.