feat: implement DID registration with JWT signing

- Add full DID registration flow matching TypeScript version
- Implement ES256K JWT signing with PEM key format
- Add async/await support for JWT operations
- Improve error handling and debug output
- Add rich documentation and type hints

Technical Changes:
- Convert private key to PEM format for JWT signing
- Match TypeScript's JWT payload structure
- Add proper JWT header with ES256K algorithm
- Implement async functions for JWT creation
- Add detailed debug output for JWT parts

Documentation:
- Add module-level docstring with flow description
- Add function-level docstrings with examples
- Document security considerations
- Add technical details and error handling info

Dependencies:
- Add cryptography for key format conversion
- Add jwcrypto for JWT operations
- Update requirements.txt with versions and comments

This commit implements the complete DID registration flow,
matching the TypeScript implementation's behavior and
adding comprehensive documentation and error handling.

test-scripts/requirements.txt

@@ -1,6 +1,11 @@
-eth-account>=0.8.0
-eth-keys>=0.4.0
-PyJWT>=2.8.0
-requests>=2.31.0
-cryptography>=41.0.0
-python-dotenv==1.0.0
+# DID Generator Python Requirements
+mnemonic>=0.20        # For seed phrase generation
+eth-account>=0.5.9    # For Ethereum account operations
+eth-keys>=0.4.0       # For key manipulation
+requests>=2.28.2      # For API communication
+typing-extensions>=4.7.1  # For type hints
+web3>=6.0.0          # For Ethereum interaction
+eth-utils>=2.1.0     # For Ethereum utilities
+pyjwt>=2.8.0        # For JWT operations
+cryptography>=42.0.0  # For key format conversion
+jwcrypto