Inject an application-generated Prisma v7 client. This is required for
the Prisma adapter because generated-client output belongs to the
application rather than this package — see
PrismaAdapterOptions, which makes that a compile error rather
than a startup throw.
A Prisma 7 client needs a driver adapter of its own
(new PrismaClient({ adapter: new PrismaPg({ connectionString }) })); the
engine-bundled new PrismaClient() constructor was removed in v7.