Zaki
367b85e991
Add WebAuthn passkey biometric unlock + dark toggle on auth screen
- Dark/light theme toggle now always visible (moved outside auth/vault sections)
- New passkey_challenges and passkey_credentials tables
- /passkey/register/begin + /passkey/register/complete endpoints
- /passkey/login/begin + /passkey/login/complete endpoints
- CBOR decoder + COSE key parser for WebAuthn attestation/assertion
- ES256 (P-256) signature verification via OpenSSL
- Client-side: register passkey button in settings, passkey login on auth screen
- First passkey login prompts for master password once to derive AES-GCM key
- Passkey login requires username input before biometric prompt