feat: Introduce signed, verifiable entries with protobuf definitions, cryptographic signing, and hashing, updating the data model and architecture.

lattice-core/src/lib.rs

@@ -7,6 +7,9 @@
 //! - **VectorClock**: Causality tracking for reconciliation
 //! - **HLC**: Hybrid Logical Clock for ordering
 //! - **Clock**: Time abstraction for testability
+//! - **Proto**: Generated protobuf types from lattice.proto
+//! - **DataDir**: Platform-specific data directory paths
+//! - **SignedEntry**: Entry creation, signing, and verification
 
 pub mod node;
 pub mod sigchain;
@@ -14,6 +17,9 @@ pub mod entry;
 pub mod vector_clock;
 pub mod hlc;
 pub mod clock;
+pub mod proto;
+pub mod data_dir;
+pub mod signed_entry;
 
 pub use node::Node;
 pub use sigchain::SigChain;
@@ -21,3 +27,5 @@ pub use entry::Entry;
 pub use vector_clock::VectorClock;
 pub use hlc::HLC;
 pub use clock::{Clock, SystemClock, MockClock};
+pub use data_dir::DataDir;
+pub use signed_entry::{EntryBuilder, sign_entry, verify_signed_entry, hash_signed_entry};