Add comprehensive usage documentation and benchmark results

- Rewrite Section 7 (Deployment Guide) with accurate CLI reference
- Add server/client command synopsis with all options
- Include correct TOML config examples with proper field names
- Add key generation (genkey/genconf) documentation
- Document all available protocols with use case recommendations
- Add local testing setup guide with 127.0.0.1 configs
- Include production deployment with systemd service
- Add troubleshooting section for common issues
- Add benchmark script and results using nooshdaroo.net/100MB
- Update protocol performance table with realistic speeds

Benchmark results (100MB download via tunnel):
- tls13_complete: 20.03 MB/s (50% of baseline)
- https: 19.03 MB/s (47% of baseline)
- tls13: 17.18 MB/s (43% of baseline)
- https_google_com: 16.57 MB/s (41% of baseline)
- tls_simple: 15.33 MB/s (38% of baseline)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: 0xinf0