feat(registry): add service discovery and health check capabilities

- Integrate tonic-health for gRPC service health monitoring
- Add etcd-based service registration with automatic keep-alive
- Implement dynamic configuration loading from etcd with fallback
- Remove external dependencies from docker-compose for simplified deployment
- Refactor service registration logic with improved lease management
- Add health service to gRPC server with serving status reporting

grpc/mod.rs

@@ -21,6 +21,8 @@ use crate::pb::im::member_service_server::MemberServiceServer;
 use crate::pb::im::permission_service_server::PermissionServiceServer;
 use crate::pb::im::stage_service_server::StageServiceServer;
 use crate::pb::im::voice_service_server::VoiceServiceServer;
+use tonic_health::ServingStatus;
+
 use crate::service::AppService;
 
 pub async fn start_grpc_server(
@@ -34,9 +36,15 @@ pub async fn start_grpc_server(
 
     let cs = channel_settings::ChannelSettingsServices::new(service);
 
+    let (health_reporter, health_service) = tonic_health::server::health_reporter();
+    health_reporter
+        .set_service_status("", ServingStatus::Serving)
+        .await;
+
     tracing::info!(%addr, "gRPC server listening");
 
     tonic::transport::Server::builder()
+        .add_service(health_service)
         .add_service(TokenServiceServer::new(token_svc))
         .add_service(ChannelServiceServer::new(channel_svc))
         .add_service(MemberServiceServer::new(member_svc))