Build the framework-agnostic core client from the ambient wagmi context, the React
layer adds NO provider of its own (decision O4). Memoized so it is stable across renders
(all hooks share it). When the chain has no MUSD deployment, createMusdClient throws
UnsupportedChain; that is captured and returned in error rather than thrown on render,
so hooks can surface it the wagmi way.
Returns {client:MusdClient|null;error:Error|null}
{ client, error }, client is null until a public client is available or
when the chain is unsupported (error then holds the UnsupportedChain).
Build the framework-agnostic core client from the ambient wagmi context, the React layer adds NO provider of its own (decision O4). Memoized so it is stable across renders (all hooks share it). When the chain has no MUSD deployment,
createMusdClientthrowsUnsupportedChain; that is captured and returned inerrorrather than thrown on render, so hooks can surface it the wagmi way.