feat(PPO_Bot): show training progress in game UI

Per-tick SVG drawText overlay above the bot showing round number and
running average reward (e.g. "R:42 avg:3.50"). Per-round summary also
printed to the UI console via printToStdOut with tick count and score.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PPO_Bot/PPO_Bot.nim

@@ -1,7 +1,7 @@
 ## PPO_Bot — enemy tracker + state vector wired into the game loop.
 ## Training: trajectory collected per tick, PPO update in background thread.
 
-import std/os
+import std/[os, strformat, strutils, math]
 import arraymancer
 import tankroyale_botapi
 import network
@@ -15,15 +15,17 @@ const botJsonPath = currentSourcePath().parentDir / "PPO_Bot.json"
 const weightsRoot = currentSourcePath().parentDir / "weights"
 
 type PPOBot = ref object of Bot
-  tracker:    EnemyTracker
+  tracker:       EnemyTracker
-  buffer:     TrajectoryBuffer
+  buffer:        TrajectoryBuffer
-  prevEnergy: float32       # own energy last tick
+  prevEnergy:    float32       # own energy last tick
-  prevEnemyE: float32       # enemy energy last tick (from tracker)
+  prevEnemyE:    float32       # enemy energy last tick (from tracker)
-  lastState:  Tensor[float32]
+  lastState:     Tensor[float32]
-  lastAction: Tensor[float32]
+  lastAction:    Tensor[float32]
-  lastLogP:   float32
+  lastLogP:      float32
-  lastValue:  float32
+  lastValue:     float32
-  hasLastTrans: bool
+  hasLastTrans:  bool
+  roundRewardSum: float32      # cumulative reward this round (for live display)
+  roundTicks:     int          # ticks this round
 
 var ac = initActorCritic()
 var gAdamStates: ACAdamStates  # persists across rounds
@@ -62,11 +64,13 @@ method onScannedBot*(bot: PPOBot, e: ScannedBotEvent) =
   bot.tracker.update(e.x, e.y, e.direction, e.speed, e.energy)
 
 method onRoundStarted*(bot: PPOBot, e: RoundStartedEvent) =
-  bot.tracker       = initEnemyTracker()
+  bot.tracker        = initEnemyTracker()
-  bot.buffer        = initTrajectoryBuffer()
+  bot.buffer         = initTrajectoryBuffer()
-  bot.prevEnergy    = 0.0'f32
+  bot.prevEnergy     = 0.0'f32
-  bot.prevEnemyE    = 0.0'f32
+  bot.prevEnemyE     = 0.0'f32
-  bot.hasLastTrans  = false
+  bot.hasLastTrans   = false
+  bot.roundRewardSum = 0.0'f32
+  bot.roundTicks     = 0
 
 method onRoundEnded*(bot: PPOBot, e: RoundEndedEventForBot) =
   inc roundCounter
@@ -76,6 +80,15 @@ method onRoundEnded*(bot: PPOBot, e: RoundEndedEventForBot) =
   if bot.hasLastTrans and bot.buffer.len > 0:
     bot.buffer.transitions[^1].reward += roundReward
 
+  # Training progress display — one line per round in the UI console
+  let ticks = bot.buffer.len
+  if ticks > 0:
+    var rewardSum = 0.0'f32
+    for tr in bot.buffer.transitions: rewardSum += tr.reward
+    let avgR = rewardSum / ticks.float32
+    let avgRStr = formatFloat(avgR.float, ffDecimal, 3)
+    printToStdOut(&"R:{roundCounter} ticks:{ticks} avgR:{avgRStr} score:{e.results.totalScore}\n")
+
   # Pick up result from previous training thread if available; channel IS the sync
   if threadLaunched:
     let (avail, trained) = resultChan.tryRecv()
@@ -144,6 +157,10 @@ method run(bot: PPOBot) =
     let enemyDelta  = curEnemyE   - bot.prevEnemyE
     let tickReward  = computeTickReward(myDelta, enemyDelta)
 
+    # Track running reward for in-game display
+    bot.roundRewardSum += tickReward
+    inc bot.roundTicks
+
     # Finalise previous transition with the reward from this tick's state change
     if bot.hasLastTrans:
       let tr = Transition(
@@ -169,6 +186,13 @@ method run(bot: PPOBot) =
     setGunTurnRate(acts.gunTurnRate.float)
     if acts.shouldFire:
       discard setFire(acts.firePower.float)
+
+    # In-game training progress overlay
+    let avgR = if bot.roundTicks > 0: bot.roundRewardSum / bot.roundTicks.float32
+               else: 0.0'f32
+    let avgRStr = formatFloat(avgR.float, ffDecimal, 2)
+    drawText(&"R:{roundCounter} avg:{avgRStr}", getX(), getY() - 40.0)
+
     go()
 
 when isMainModule: