server: expose subscription runtime catalog

crates/workspace-server/src/runtime_subscription.rs

@@ -200,6 +200,18 @@ impl RuntimeSubscriptionBroker {
         }
     }
 
+    pub fn runtime_ids(&self) -> Vec<String> {
+        let mut runtime_ids = self
+            .registrations
+            .read()
+            .expect("broker registry poisoned")
+            .keys()
+            .cloned()
+            .collect::<Vec<_>>();
+        runtime_ids.sort();
+        runtime_ids
+    }
+
     pub fn status(&self, runtime_id: &str) -> Option<RuntimeSubscriptionBrokerStatus> {
         let status = self
             .registrations

crates/workspace-server/src/runtime_subscription_tests.rs

@@ -283,6 +283,7 @@ async fn embedded_runtime_uses_in_process_subscription_source() {
     let worker = runtime.list_workers().unwrap().remove(0);
     let broker = RuntimeSubscriptionBroker::new("local");
     broker.register_embedded_runtime("embedded-worker-runtime", runtime.clone());
+    assert_eq!(broker.runtime_ids(), vec!["embedded-worker-runtime"]);
     let mut subscription = broker
         .subscribe(
             "embedded-worker-runtime",