Use client.submit() with for-await to stream data events

Gradio JS client exposes streaming via submit() returning an async
iterator, not a stream() event emitter. Iterate over msg.type=='data'
events to receive partial chunks.

Co-Authored-By: Claude <noreply@anthropic.com>

index.html

@@ -350,13 +350,14 @@ async function submit() {
     let fullText = "";
     let renderQueued = false;
 
-    const stream = client.stream("/chat", {
+    const submission = client.submit("/chat", {
       message: gradioMsg,
       history: history.slice(0, -1),
     });
 
-    stream.on("data", (chunk) => {
-      const data = chunk?.data?.[0];
+    for await (const msg of submission) {
+      if (msg.type !== "data") continue;
+      const data = msg?.data?.[0];
       const txt = typeof data === "object" ? (data?.content || "") : (data || "");
       if (txt) {
         fullText = txt;
@@ -368,12 +369,7 @@ async function submit() {
           });
         }
       }
-    });
-
-    await new Promise((resolve, reject) => {
-      stream.on("end", resolve);
-      stream.on("error", reject);
-    });
+    }
 
     history.push({ role: "assistant", content: fullText });
   } catch (err) {