A client shared across inbounds (e.g. VLESS+TCP+Reality and VLESS+WS+TLS)
had its `flow` applied globally, so enabling xtls-rprx-vision for Reality
broke the WS+TLS inbound for the same client (#4628).
Gate flow per inbound at every fan-out site via clientWithInboundFlow,
reusing inboundCanEnableTlsFlow (VLESS+TCP+TLS/Reality only), and make
ListForInbound treat flow_override as authoritative so an empty override
means "no flow on this inbound" instead of inheriting the record's global
flow. Also tighten buildTargetClientFromSource (copy-clients) to gate on
transport, not just protocol.
7ea88e3e37