feat: Implement DAG-based conflict resolution with binary keys and multi-head CLI display

lattice-core/src/lib.rs

@@ -41,4 +41,5 @@ pub use signed_entry::{EntryBuilder, sign_entry, verify_signed_entry, hash_signe
 pub use log::{append_entry, read_entries, LogReader};
 pub use store::Store;
 pub use meta_store::MetaStore;
+pub use proto::HeadInfo;
 pub use uuid::Uuid;

lattice-core/src/proto.rs

@@ -33,6 +33,7 @@ mod tests {
             version: 1,
             store_id: vec![1u8; 16],
             prev_hash: vec![0u8; 32],
+            parent_hashes: vec![],
             seq: 5,
             timestamp: Some(Hlc {
                 wall_time: 1000,
@@ -41,7 +42,7 @@ mod tests {
             ops: vec![
                 Operation {
                     op_type: Some(operation::OpType::Put(PutOp {
-                        key: "/nodes/abc".to_string(),
+                        key: b"/nodes/abc".to_vec(),
                         value: b"hello".to_vec(),
                     })),
                 },

lattice-core/src/sigchain.rs

@@ -451,7 +451,7 @@ mod tests {
         let ops = vec![
             Operation {
                 op_type: Some(operation::OpType::Put(PutOp {
-                    key: "/test".to_string(),
+                    key: b"/test".to_vec(),
                     value: b"hello".to_vec(),
                 })),
             },

lattice-core/src/signed_entry.rs

@@ -34,6 +34,7 @@ pub struct EntryBuilder {
     version: u32,
     store_id: Vec<u8>,
     prev_hash: Vec<u8>,
+    parent_hashes: Vec<Vec<u8>>,
     seq: u64,
     timestamp: HLC,
     ops: Vec<Operation>,
@@ -44,8 +45,9 @@ impl EntryBuilder {
     pub fn new(seq: u64, timestamp: HLC) -> Self {
         Self {
             version: 1,
-            store_id: Vec::new(), // Empty = legacy single-store
-            prev_hash: vec![0u8; 32], // Genesis or will be set
+            store_id: Vec::new(),
+            prev_hash: vec![0u8; 32],
+            parent_hashes: Vec::new(),
             seq,
             timestamp,
             ops: Vec::new(),
@@ -58,14 +60,20 @@ impl EntryBuilder {
         self
     }
 
-    /// Set the previous entry hash (for chaining)
+    /// Set the previous entry hash (for sigchain linking)
     pub fn prev_hash(mut self, hash: impl Into<Vec<u8>>) -> Self {
         self.prev_hash = hash.into();
         self
     }
 
+    /// Set the parent hashes (for DAG ancestry)
+    pub fn parent_hashes(mut self, hashes: Vec<Vec<u8>>) -> Self {
+        self.parent_hashes = hashes;
+        self
+    }
+
     /// Add a Put operation
-    pub fn put(mut self, key: impl Into<String>, value: impl Into<Vec<u8>>) -> Self {
+    pub fn put(mut self, key: impl Into<Vec<u8>>, value: impl Into<Vec<u8>>) -> Self {
         self.ops.push(Operation {
             op_type: Some(operation::OpType::Put(PutOp {
                 key: key.into(),
@@ -76,7 +84,7 @@ impl EntryBuilder {
     }
 
     /// Add a Delete operation
-    pub fn delete(mut self, key: impl Into<String>) -> Self {
+    pub fn delete(mut self, key: impl Into<Vec<u8>>) -> Self {
         self.ops.push(Operation {
             op_type: Some(operation::OpType::Delete(DeleteOp {
                 key: key.into(),
@@ -97,6 +105,7 @@ impl EntryBuilder {
             version: self.version,
             store_id: self.store_id,
             prev_hash: self.prev_hash,
+            parent_hashes: self.parent_hashes,
             seq: self.seq,
             timestamp: Some(Hlc {
                 wall_time: self.timestamp.wall_time,