- Enhanced the Signer struct to include a FallbackSigner for scenarios where the libsecp256k1 implementation is unavailable.
- Updated the New function to initialize the fallback signer when the context creation fails.
- Refactored methods in the Signer to delegate operations to the FallbackSigner when applicable, ensuring compatibility with pure Go implementations.
- Added comprehensive method implementations for the FallbackSigner, including key generation, signing, and verification.
- Improved error handling and memory management in the new implementation.