⚡ Bolt: Zero-allocation refill optimization

[google-labs-jules]

💡 What:

• Replaced AtomicInteger.updateAndGet() with a manual compareAndSet loop in TokenBucketLimiter.refill().
• Added a check to clamp tokensToAdd to capacity immediately if periodsElapsed is large enough.

🎯 Why:

• GC Pressure: The original code used a capturing lambda current -> Math.min(capacity, current + tokensToAdd) which allocates a new object every time refill() successfully updates tokens. In a high-throughput rate limiter, this creates significant garbage.
• CPU Efficiency: If the limiter is idle for a long time, calculating periodsElapsed * refillTokens is unnecessary if we know it exceeds capacity. The optimization skips this multiplication.
• Safety: Prevents potential long overflow if periodsElapsed becomes extremely large (though rare).

📊 Impact:

• Reduces object allocation rate in the critical path (zero-allocation refill).
• Reduces CPU cycles for refill calculations after long idle periods.

🔬 Measurement:

• Verify with pnpm test (or ./gradlew test).
• Functional behavior remains identical, but micro-benchmarks would show reduced GC activity.

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PR created automatically by Jules for task 11331851479498510601 started by @SpaceLeam

[google-labs-jules]

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