queryClient.ts constructed the TanStack client at module eval but was not
in the sideEffects allowlist, so Rollup treated the module as pure — safe
only while a value-importer keeps it alive (D-3).
- replace the eager `queryClient` singleton with a memoized getQueryClient()
factory; construction is deferred to first call
- the module is now genuinely side-effect-free, so no sideEffects exception
is needed and construction can never be legally tree-shaken away
- route all consumers through getQueryClient() (QueryProvider as first
caller; stores via class fields/observers; tests via a local alias; the
fontCatalogStore spec mock now overrides getQueryClient)