Added #ifdef __cplusplus / extern "C" { ... } / #endif to ~65 headers in src/ and lib/, enabling the C library to be linked into C++ code (chatgui). Fixed packet_dump.h (added missing header guard) and etcp_bbr.h (#pragma once guard).
- get_default_route_netif_index(): UDP connect trick + getifaddrs to find default route iface - etcp_socket_add(): auto-detect netif_index when not specified in config - queue_new() API: explicit index_offset/index_size params instead of implicit from hash_size - radix: cleanup types (uint8_t*), replace bzero/bcmp with memset/memcmp, remove kernel ifdefs - route6_lib: new IPv6 routing library + get_node_v6_routes()