- Add ES256K signature generation for test claims
- Fix signature format to match endorser.ch requirements
- Remove dependency on did_generator.sh for signing
- Improve JWT creation with proper header and payload structure
The changes fix JWT verification issues by:
1. Implementing proper DER to R+S signature conversion
2. Handling secp256k1 private key formatting correctly
3. Using correct base64url encoding for JWT components
4. Adding proper issuer field to JWT payload