feat: Add comprehensive performance benchmark suite

Node.js Baseline Benchmarks (✅ Complete):
- 10 comprehensive benchmarks across database operations
- 5 iterations per test for statistical accuracy
- Baseline metrics: 0.01-0.58ms avg, 1,713-94,341 ops/sec
- Results exported to benchmark-node.json

Browser Benchmark Infrastructure (Ready for Testing):
- benchmark.html: Interactive browser benchmark page
- benchmark.ts: TypeScript benchmark suite
- VFS detection and comparison tools
- Real-time performance comparison with Node.js baseline

Documentation:
- docs/benchmark-results.md: Comprehensive performance analysis
- Target: Browser <2x slower than Node.js
- Testing matrix for Chrome, Firefox, Safari
- Performance methodology and criteria

Key Metrics (Node.js):
- Single Insert: 60,000 ops/sec
- Transaction (1000 rows): 1,713 ops/sec
- Graph Traversal: 20,367 ops/sec
- All operations < 1ms average

Next Steps:
- Manual browser testing via benchmark.html
- Cross-browser performance validation
- Document browser results in benchmark-results.md

Co-Authored-By: Claude <[email protected]>

Author: michaeloboyle