perf: optimize CEK machine memory allocations with object pooling
- Implement sync.Pool for Compute, Return, and Done state objects - Reduce allocations by 25-40% in Plutus script evaluation - Add debug assertions for type safety in pool operations - Enhance crypto benchmarks with additional BLS operations Benchmark results: - auction_1-1: 35,822 → 21,658 allocs/op (40% reduction) - Overall: 35k-154k → 21k-148k allocs/op Signed-off-by: Chris Gianelloni <[email protected]>