diag(SNNBot): revert to baseline, add bias diagnostics

Reverted fire gate from 1° back to 2°, removed gridHasData cold-start
guard so bot fires on straight aim during cold-start. Added
/tmp/snnbot_bias_debug.log BIAS entries in EVALUATE phase logging
gridOffset, correctOffset, bias, vPerp, dist per cycle.

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

SNNBot_garage/src/SNNBot.nim

@@ -18,6 +18,7 @@ import reservoir
 let diagnosticLog  = "/tmp/snnbot_diagnostic.log"
 let roundStatsLog  = "/tmp/snnbot_round_stats.log"
 let aimDebugLog    = "/tmp/snnbot_aim_debug.log"
+let biasDebugLog   = "/tmp/snnbot_bias_debug.log"
 
 proc diagLog(s: string) =
   try:
@@ -334,6 +335,7 @@ method onGameStarted*(bot: SNNBot, e: GameStartedEventForBot) =
   bot.res = initLeadGrid()
   truncateLog(roundStatsLog)
   truncateLog(aimDebugLog)
+  truncateLog(biasDebugLog)
 
 
 method onBulletFired*(bot: SNNBot, e: BulletFiredEvent) =
@@ -425,7 +427,7 @@ method run*(bot: SNNBot) =
       let leadOffset = normalizeRelativeAngle(bot.targetAngle - bot.lastAbsBearing)
       appendLog(aimDebugLog, fmt"TICK t={bot.roundTick} err={err:.2f} offset={leadOffset:.2f} vPerp={bot.lastVPerp:.2f} dist={bot.enemyDist:.1f}")
 
-      let readyToFire = err < 1.0 and energy >= ENERGY_GUARD and bot.roundTick >= PATIENCE_TICKS and bot.gridHasData
+      let readyToFire = err < 2.0 and energy >= ENERGY_GUARD and bot.roundTick >= PATIENCE_TICKS
       if readyToFire:
         discard setFire(FIRE_POWER)
         bot.phase = EVALUATE
@@ -451,6 +453,9 @@ method run*(bot: SNNBot) =
           # correctOffset: angle offset from bare bearing that a bullet at BULLET_SPEED needs
           let correctOffset = normalizeRelativeAngle(correctAngle - bot.lastAbsBearing)
           let producedOffset = bot.res.forward(bot.lastVPerp, bot.enemyDist)
+          # Bias diagnostics: log grid offset vs correct offset to detect systematic error
+          let biasVal = producedOffset - correctOffset
+          appendLog(biasDebugLog, fmt"BIAS tick={bot.roundTick} gridOffset={producedOffset:.3f} correctOffset={correctOffset:.3f} bias={biasVal:.3f} vPerp={bot.lastVPerp:.3f} dist={bot.enemyDist:.1f}")
 
           # Learn if: cold start OR error > dead zone
           if producedOffset > -999.0:

SNNBot_garage/tests/test_bullet_economy.nim

@@ -31,7 +31,7 @@ const
 
 let wallsbotDir = sampleBotsDir / "Walls"
 
-const ROUNDS = 20
+const ROUNDS = 50
 
 let r = runBattle(@[snnbotDir, wallsbotDir], rounds = ROUNDS)