Add `set_forwarded_host` and `set_forwarded_proto` options to control
whether the proxy automatically sets these headers. This fixes issues
with upstream servers that validate X-Forwarded-Host against known hosts.
Changes:
- Add SetForwardedHost/SetForwardedProto fields to ProxyHeaders struct
- Modify SetForwardedHeaders and WriteForwardedHeaders function signatures
- Update modifyRequestHeaders to read config and pass control parameters
- Update WebSocket call chain to support new config
- Add unit tests for new functionality
- Update default config generation (-g) to include new options
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
