refactor(actor): implement replica sync and ref update notification system

- Add is_write parameter to remote clients for read/write routing distinction
- Introduce RepoEntry struct with role tracking (primary/replica) for repositories
- Replace HashSet with HashMap for repository storage with role metadata
- Add ROLE_PRIMARY and ROLE_REPLICA constants for node role identification
- Implement FindPrimary and FindReplica RPC methods for role-based routing
- Add RefUpdateEvent message type for propagating reference updates
- Create sync module with BundleApplicator for handling replica synchronization
- Implement notify_ref_update calls after branch/tag/commit operations
- Add broadcast_ref_update function to propagate events across cluster nodes
- Modify route_repository to prioritize primary for writes and replicas for reads
- Update actor message handling to support role-based repository discovery
- Implement sync_from_primary function using pack protocol for incremental updates

actor/message.rs

@@ -13,6 +13,9 @@ impl BytesConvertable for RepositoryHeader {
     }
 }
 
+pub const ROLE_PRIMARY: &str = "primary";
+pub const ROLE_REPLICA: &str = "replica";
+
 #[derive(Debug, Clone)]
 pub struct RouteDecision {
     pub found: bool,
@@ -20,6 +23,7 @@ pub struct RouteDecision {
     pub relative_path: String,
     pub actor_name: String,
     pub grpc_addr: String,
+    pub role: String,
 }
 
 impl BytesConvertable for RouteDecision {
@@ -30,6 +34,7 @@ impl BytesConvertable for RouteDecision {
             self.relative_path,
             self.actor_name,
             self.grpc_addr,
+            self.role,
         ])
     }
 
@@ -41,6 +46,7 @@ impl BytesConvertable for RouteDecision {
             relative_path: values.get(2).cloned().unwrap_or_default(),
             actor_name: values.get(3).cloned().unwrap_or_default(),
             grpc_addr: values.get(4).cloned().unwrap_or_default(),
+            role: values.get(5).cloned().unwrap_or_default(),
         }
     }
 }
@@ -74,6 +80,41 @@ impl BytesConvertable for NodeHealth {
     }
 }
 
+#[derive(Debug, Clone)]
+pub struct RefUpdateEvent {
+    pub relative_path: String,
+    pub ref_name: String,
+    pub old_oid: String,
+    pub new_oid: String,
+    pub primary_grpc_addr: String,
+    pub primary_storage_name: String,
+}
+
+impl BytesConvertable for RefUpdateEvent {
+    fn into_bytes(self) -> Vec<u8> {
+        encode_strings(&[
+            self.relative_path,
+            self.ref_name,
+            self.old_oid,
+            self.new_oid,
+            self.primary_grpc_addr,
+            self.primary_storage_name,
+        ])
+    }
+
+    fn from_bytes(bytes: Vec<u8>) -> Self {
+        let values = decode_strings(bytes);
+        Self {
+            relative_path: values.first().cloned().unwrap_or_default(),
+            ref_name: values.get(1).cloned().unwrap_or_default(),
+            old_oid: values.get(2).cloned().unwrap_or_default(),
+            new_oid: values.get(3).cloned().unwrap_or_default(),
+            primary_grpc_addr: values.get(4).cloned().unwrap_or_default(),
+            primary_storage_name: values.get(5).cloned().unwrap_or_default(),
+        }
+    }
+}
+
 #[derive(RactorClusterMessage)]
 pub enum GitNodeMessage {
     ScanAndRegister,
@@ -82,8 +123,13 @@ pub enum GitNodeMessage {
 
     RemoveRepository(RepositoryHeader),
 
+    RefUpdated(RefUpdateEvent),
+
     #[rpc]
-    RouteRepository(RepositoryHeader, RpcReplyPort<RouteDecision>),
+    FindPrimary(RepositoryHeader, RpcReplyPort<RouteDecision>),
+
+    #[rpc]
+    FindReplica(RepositoryHeader, RpcReplyPort<RouteDecision>),
 
     #[rpc]
     ListRepositoryPaths(RpcReplyPort<String>),