the panel rejected configurations like vless reality on tcp/443 and
hysteria2 on udp/443 even though those are independent sockets in
linux. the old checkPortExist looked only at port + listen.
inboundTransports now classifies each inbound by L4 transport:
hysteria/hysteria2/wireguard are udp; streamSettings.network=kcp is
udp; shadowsocks reads settings.network ("tcp"/"udp"/"tcp,udp");
mixed (socks/http) adds udp when settings.udp is true; everything
else is tcp. checkPortConflict pulls every row on the same port and
only flags a conflict when transport masks overlap. the listen-
overlap rule (specific addr vs any-addr on the same port) is kept.
inbounds.tag has a unique DB constraint and the controller derives
tags from port ("inbound-443"). without disambiguation a second
inbound on the same port would still hit a unique-constraint error.
generateInboundTag keeps the historical "inbound-<port>" shape when
the base tag is free, so existing routing rules survive the upgrade
unchanged, and appends "-tcp"/"-udp" only when the base is already
taken.
closes#4103.
