Contract: pass approval option warnings, omit threadId on host pushes

gateway/src/main.ts

@@ -35,7 +35,7 @@ const sendPush: SendPush = async (push) => {
       alert: { title: push.title, ...(push.subtitle ? { subtitle: push.subtitle } : {}), body: push.body },
       sound: "default",
       category: push.category,
-      "thread-id": push.data.threadId || push.data.hostId,
+      "thread-id": push.data.threadId ?? push.data.hostId,
     },
     ...push.data,
   };