feat(credential): improve credential peer routing and visibility (#1971)

- improve credential peer filtering and related route lookup behavior
- expose credential peer information through CLI and API definitions
- add and refine tests for credential routing and peer interactions

easytier/src/tests/credential_tests.rs

@@ -708,6 +708,18 @@ async fn credential_revocation_propagates() {
     )
     .await;
 
+    wait_for_condition(
+        || async { !ping_test("ns_adm", "10.144.144.2", None).await },
+        Duration::from_secs(10),
+    )
+    .await;
+
+    wait_for_condition(
+        || async { !ping_test("ns_c1", "10.144.144.1", None).await },
+        Duration::from_secs(10),
+    )
+    .await;
+
     drop_insts(vec![admin_inst, cred_inst]).await;
 }