- Added IIssuerDirectory interface for managing VEX document issuers, including methods for registration, revocation, and trust validation.
- Created InMemoryIssuerDirectory class as an in-memory implementation of IIssuerDirectory for testing and single-instance deployments.
- Introduced ISignatureVerifier interface for verifying signatures on VEX documents, with support for multiple signature formats.
- Developed SignatureVerifier class as the default implementation of ISignatureVerifier, allowing extensibility for different signature formats.
- Implemented handlers for DSSE and JWS signature formats, including methods for verification and signature extraction.
- Defined various records and enums for issuer and signature metadata, enhancing the structure and clarity of the verification process.
- Introduced `ReachabilityState`, `RuntimeHit`, `ExploitabilitySignal`, `ReachabilitySignal`, `SignalEnvelope`, `SignalType`, `TrustSignal`, and `UnknownSymbolSignal` records to define various signal types and their properties.
- Implemented JSON serialization attributes for proper data interchange.
- Created project files for the new signal contracts library and corresponding test projects.
- Added deterministic test fixtures for micro-interaction testing.
- Included cryptographic keys for secure operations with cosign.
