v0.1.0 of envault

Fintech-grade secret management for Flutter/Dart. AES-256-GCM encryption in generated code, SecureString type, build-time validation, and git hygiene enforcement. The only Dart package with a derived [...] Changelog excerpt: - Initial release of envault. - Introduced AES-256-GCM encryption for secrets. - Added SecureStringwith .use()scope to prevent log leakage. - Implemented PBKDF2 derived keys at runtime (master key not stored in binary). - Integrated hardware acceleration via cryptography_flutter.