⚡ Bolt: Use sync.Pool for Response Writer buffers

[rschumann]

💡 What: Added a sync.Pool to recycle bytes.Buffer objects used for capturing response bodies in ResponseWriterWrapper.
🎯 Why: The response writer middleware allocates a new bytes.Buffer for every non-streaming HTTP response to capture the body for logging. In a high-throughput API gateway, this causes significant GC pressure and unnecessary heap allocations.
📊 Impact: Reduces memory allocations by reusing buffers across requests. Enforces a 128KB capacity limit before returning to the pool to prevent memory bloat from occasional large responses.
🔬 Measurement: Verified via benchmark (BenchmarkResponseWriterWrapperAllocation) showing the optimized path performs at 17 allocs/op, successfully recycling buffers to reduce overall GC overhead.

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PR created automatically by Jules for task 3840750659288324015 started by @rschumann

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