Copolit:

Add playlist encryption and anonymous creation features

Introduced `EncryptedPlaylistData` to store encrypted playlist metadata. Added `AnonymousPlaylistHelper` for generating anonymous playlist details. Implemented `PlaylistEncryption` for AES-256 encryption/decryption of playlist data, with local storage support.

Enhanced `Program` and `APIHelper` classes with new operations for creating anonymous playlists, encrypting/decrypting playlists, exporting encrypted backups, and managing local storage. Improved playlist and video handling with better output formatting and interactive privacy updates.

Strengthened security with password-based encryption and ensured offline storage of sensitive data. Added error handling, user prompts, and documentation updates for improved usability and maintainability.

Author: ewdlop