The generated models.d.ts is present in the src directory of the NPM package, but not in the dist directory.
The result is that
import { models } from "@pydantic/fastui";
doesn't give type hints, and doesn't do type checking.
I've worked around this for now by doing
cp node_modules/@pydantic/fastui/src/models.d.ts node_modules/@pydantic/fastui/dist/
as part of my "dev" step.