[router] move tokenizer, reasoning, tool initialization to server (#9996)

sgl-router/tests/common/test_app.rs

@@ -15,12 +15,15 @@ pub fn create_test_app(
     router_config: &RouterConfig,
 ) -> Router {
     // Create AppContext
-    let app_context = Arc::new(AppContext::new(
-        router_config.clone(),
-        client,
-        router_config.max_concurrent_requests,
-        router_config.rate_limit_tokens_per_second,
-    ));
+    let app_context = Arc::new(
+        AppContext::new(
+            router_config.clone(),
+            client,
+            router_config.max_concurrent_requests,
+            router_config.rate_limit_tokens_per_second,
+        )
+        .expect("Failed to create AppContext in test"),
+    );
 
     // Create AppState with the test router and context
     let app_state = Arc::new(AppState {