- Add arrayToBase64/base64ToArray conversion functions - Add deriveKey for PBKDF2 key derivation - Add encrypt/decrypt using AES-GCM - Add generateMasterKey for random key generation - Update setup.ts to use real Web Crypto API instead of mock - Add comprehensive unit tests for all crypto functions Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>