fix(PPO_Bot): round_counter always written after increment

Early-return guard on empty buffer was skipping round_counter.txt write,
causing training script to think bot crashed (counter stuck at 0).

PPO_Bot/PPO_Bot.nim

@@ -139,6 +139,8 @@ method onRoundEnded*(bot: PPOBot, e: RoundEndedEventForBot) =
     printToStdOut(&"R:{roundCounter} ticks:{ticks} buf:{bot.buffer.len} sinceUpd:{roundsSinceUpdate}/{hpUpdateInterval} avgR:{avgRStr} score:{e.results.totalScore}\n")
     echo &"R:{roundCounter} ticks:{ticks} buf:{bot.buffer.len} sinceUpd:{roundsSinceUpdate}/{hpUpdateInterval} avgR:{avgRStr} score:{e.results.totalScore}"
 
+  writeFile(weightsRoot / "round_counter.txt", $roundCounter)
+
   if bot.buffer.len == 0:
     bot.hasLastTrans = false
     return
@@ -152,7 +154,6 @@ method onRoundEnded*(bot: PPOBot, e: RoundEndedEventForBot) =
   # checkpoint save, but keep advancing/writing round_counter.txt so run.sh's
   # remaining-rounds bookkeeping still works, and keep the game line above.
   if evalOnly:
-    writeFile(weightsRoot / "round_counter.txt", $roundCounter)
     bot.buffer.clear()
     bot.hasLastTrans = false
     roundsSinceUpdate = 0