refactor(actor): implement Raft consensus algorithm for cluster leader election

- Add voting mechanism with term tracking and vote persistence
- Implement election triggering logic with majority vote counting
- Add primary/replica role transition handling with state management
- Integrate health check failure detection for automatic elections
- Refactor actor messaging system for distributed coordination
- Update repository registration to query cluster for existing primary
- Add broadcast mechanism for role change notifications
- Implement proper term comparison and duplicate request filtering
- Upgrade dependency versions including tokio-util for async utilities
- Optimize code formatting and line wrapping for improved readability
- Remove redundant blank lines and improve code structure consistency
- Enhance error logging and trace information for debugging purposes

actor/mod.rs

@@ -3,6 +3,7 @@ pub mod message;
 pub mod server;
 pub mod sync;
 
+pub use handler::find_primary_in_cluster;
 pub use handler::{
     GitNodeActor, GitNodeArgs, RepoEntry, broadcast_ref_update, broadcast_role_changed,
     get_category_members, get_cluster_nodes, list_all_groups, route_group_for, start_node_actor,