another fix for human choices

frontend/src/pages/HumanFightPage.vue

@@ -123,9 +123,15 @@ function handleKeyboard(e: KeyboardEvent) {
   }
 }
 
+let pollBackoff = 0
+
 function startPolling() {
+  pollBackoff = 0
   pollForChallenge()
-  pollHandle = setInterval(pollForChallenge, 600)
+  pollHandle = setInterval(() => {
+    if (pollBackoff > 0) { pollBackoff--; return }
+    pollForChallenge()
+  }, 800)
 }
 
 function stopPolling() {
@@ -172,7 +178,9 @@ async function pollForChallenge() {
 
   try {
     const res = await fetch(`/api/fights/${fightId.value}/challenge/${myBotId.value}`)
+    if (res.status === 429) { pollBackoff = Math.min(pollBackoff + 2, 8); return }
     if (!res.ok) return
+    pollBackoff = Math.max(0, pollBackoff - 1)
     const data = await res.json()
 
     // Reset error tracking on success