How it works:
1. VPN configures NymNetworkDetails with front_hosts
2. SDK passes network_details to BaseClientBuilder via with_network_details()
3. BaseClientBuilder uses ClientBuilder::from_network() when available
4. from_network() automatically enables domain fronting if front_hosts configured
Benefits:
- Configuration-based (network_details), not object-based (cleaner)
- No breaking changes for existing clients
Changes:
- Added network_details: Option<NymNetworkDetails> to BaseClientBuilder
- Updated tests
Tommy Verrall
62967f736d