refactor: modularize api server assets and handlers

server-rs/crates/api-server/src/modules/health.rs

@@ -0,0 +1,7 @@
+use axum::{Router, routing::get};
+
+use crate::{health::health_check, state::AppState};
+
+pub fn router(_state: AppState) -> Router<AppState> {
+    Router::new().route("/healthz", get(health_check))
+}