Add EncryptID as a DRF authentication class:
- Add encryptid_auth.py with EncryptIDAuthentication backend
- Verifies Bearer tokens against EncryptID server
- Auto-creates Django User from DID claims
- Add ENCRYPTID_SERVER_URL and ENCRYPTID_JWT_SECRET settings
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
