Audit this code for performance issues: [PASTE CODE OR DESCRIBE THE BOTTLENECK]. Current performance: [METRICS IF KNOWN]. Expected performance target: [DEFINE]. Analyze: 1) Algorithmic complexity — identify O(n²) or worse patterns, 2) Database query efficiency (N+1, missing indexes, over-fetching), 3) Memory allocation patterns and potential leaks, 4) I/O blocking operations that should be async, 5) Caching opportunities, 6) Unnecessary computation or redundant calls. Prioritize fixes by impact. Provide benchmarks before/after for the top recommendations.