Performance optimization for large-scale deployments

## Description
Optimize ZeroTrace for handling thousands of agents and millions of vulnerabilities.

## Optimization Areas
- [ ] Database query optimization
- [ ] Cache strategy refinement
- [ ] Queue processing optimization
- [ ] API response time improvement
- [ ] Memory usage optimization
- [ ] Network I/O optimization

## Performance Targets
- [ ] Support 10,000+ concurrent agents
- [ ] Process 1M+ vulnerabilities per hour
- [ ] API response time < 100ms
- [ ] Database query time < 50ms
- [ ] Memory usage < 2GB per service

## Priority: Medium
**Type**: Performance
**Component**: All
**Estimated Effort**: 2-3 weeks

No files, tests, or entry points are named. Start by mapping ZeroTrace's database, cache, queue, API, memory, and network paths, then establish measurements for the listed scale and response targets; done means meeting all stated concurrency, throughput, latency, query-time, and memory goals.

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