- Encrypt sensitive credentials (tokens, passwords) in backup exports
using AES-256-GCM with PBKDF2 key derivation from OS username
- Backup format v2 with backwards-compatible v1 import
- Show dialog to create non-existent directories when changing
outputDir, extractDir, or mkvLibraryDir settings
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>