add default thread (when none found)

src/App.svelte

@@ -36,6 +36,7 @@
 
     onMount(async () => {
       keyAsstAndThread = await getKeyAsstAndThread();
+      threads = getThreads();
       chat_name = keyAsstAndThread[2]?.name ? keyAsstAndThread[2].name : "";
     });
 

src/threadUtils.js

@@ -29,6 +29,8 @@ export async function getThread() {
 
     setThreads([new_thread]);
     setThread(new_thread);
+
+    return new_thread;
   }
 
   return null;