[router] Implement HTTP Dependency Injection Pattern for Router System (#8714)

sgl-router/src/service_discovery.rs

@@ -40,7 +40,6 @@ impl Default for ServiceDiscoveryConfig {
             check_interval: Duration::from_secs(60),
             port: 8000,      // Standard port for modern services
             namespace: None, // None means watch all namespaces
-            // PD mode defaults
             pd_mode: false,
             prefill_selector: HashMap::new(),
             decode_selector: HashMap::new(),
@@ -581,7 +580,8 @@ mod tests {
         use crate::routers::router::Router;
 
         let policy = PolicyFactory::create_from_config(&PolicyConfig::Random);
-        let router = Router::new(vec![], policy, 5, 1, false, None).unwrap();
+        let router =
+            Router::new(vec![], policy, reqwest::Client::new(), 5, 1, false, None).unwrap();
         Arc::new(router) as Arc<dyn RouterTrait>
     }