fix(SNNBot): fast recovery on target move + bidirectional fire gate

Problem 1: Dead zone (skip learn when error < 1.5°) means stale exemplars
linger in ring buffer after target moves. Fix: detect error jump >5° and
reset ring buffer (aimer.count, aimer.nextSlot = 0) for fresh start.

Problem 2: Fire gate only checked start condition (err < threshold), never
stopped firing when error worsened. Fix: explicit setFire(0.0) when error
exceeds tolerance, making gate bidirectional (start and stop).

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

SNNBot_garage/src/SNNBot.nim

@@ -215,6 +215,7 @@ type
     velSpeed:        float64            # speed (units/tick) from last scan delta
     lastDecideGunDir: float             # gun heading captured at DECIDE time for EVALUATE
     lastBinInput:    BitVec80           # DECIDE-time binary input, reused in EVALUATE
+    lastError:       float              # last aiming error (for jump detection)
 
 # ── aimTo helper ──────────────────────────────────────────────────────────────
 
@@ -273,6 +274,7 @@ method onRoundStarted*(bot: SNNBot, e: RoundStartedEvent) =
   bot.velSpeed     = 0.0
   bot.phase        = DECIDE
   bot.tick         = 0
+  bot.lastError    = -1.0      # sentinel: no error yet
   setTargetSpeed(0.0)
   setTurnRate(0.0)
 
@@ -382,9 +384,21 @@ method run*(bot: SNNBot) =
     of WAITING:
       aimTo(bot.targetAngle, gunDir)
       let err = abs(normalizeRelativeAngle(bot.targetAngle - gunDir))
+
+      # Bidirectional fire gate: fire only when error within tolerance
       if err < AIM_TOL:
         discard setFire(FIRE_POWER)
         bot.phase = EVALUATE
+      else:
+        discard setFire(0.0)
+
+      # Fast recovery: detect error jump (regime change) and reset ring buffer
+      # ponytail: >5° jump triggers reset; tune threshold if target moves frequently
+      if bot.lastError >= 0.0 and err - bot.lastError > 5.0:
+        bot.res.count = 0
+        bot.res.nextSlot = 0
+
+      bot.lastError = err
 
     of EVALUATE:
       # Predictive error signal: extrapolate enemy position at bullet impact time.