This allows for helpers like the following to work intuitively for all
types of "input fields". It also establishes the intended mental
philosophy that a model is both an input and an output.
```ts
/** Unwraps all signal input properties. */
export type UnwrapSignalInputs<T> = {
[K in keyof T]: T[K] extends InputSignalWithTransform<any, infer WriteT>
? WriteT
: T[K];
};
```
PR Close#56452