[fix](trx-frontend-http): flush live decode buffer only after history drain completes

drainDecodeHistory() chunks work via setTimeout but flushLiveBuffer() was
called synchronously right after starting the drain, so live messages could
interleave with in-progress history chunks. Pass flushLiveBuffer as an
onDone callback so live messages are only dispatched once all history chunks
have been processed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js

@@ -6162,11 +6162,15 @@ function dispatchDecodeMessage(msg) {
   if (msg.type === "wspr" && window.onServerWspr) window.onServerWspr(msg);
 }
 
-function drainDecodeHistory(buffer, index) {
+function drainDecodeHistory(buffer, index, onDone) {
   const CHUNK = 30;
   const end = Math.min(index + CHUNK, buffer.length);
   for (let i = index; i < end; i++) dispatchDecodeMessage(buffer[i]);
-  if (end < buffer.length) setTimeout(() => drainDecodeHistory(buffer, end), 0);
+  if (end < buffer.length) {
+    setTimeout(() => drainDecodeHistory(buffer, end, onDone), 0);
+  } else if (typeof onDone === "function") {
+    onDone();
+  }
 }
 
 function connectDecode() {
@@ -6224,8 +6228,11 @@ function connectDecode() {
     return resp.json();
   }).then((msgs) => {
     clearTimeout(historyTimeout);
-    if (Array.isArray(msgs)) drainDecodeHistory(msgs, 0);
-    flushLiveBuffer();
+    if (Array.isArray(msgs) && msgs.length > 0) {
+      drainDecodeHistory(msgs, 0, flushLiveBuffer);
+    } else {
+      flushLiveBuffer();
+    }
   }).catch(() => { clearTimeout(historyTimeout); flushLiveBuffer(); });
 }
 if (document.readyState === "complete") {