Unifies IPv4 and IPv6 default route queries under a shared result structure and per-family functions. Improves clarity and extensibility by centralizing route logic, streamlining detection of preferred interfaces, and updating all consumers to use the new API.
Prepares for more robust multi-protocol network information handling.
* LocalIP: consider preferred source address when retrieving default route
* LocalIP: fix logic error when there is no preferred source address
* LocalIP: use macros rather than manual free/close
* LocalIP(BSD): fix build error
* LocalIP: address Copilot suggestions
李通洲