bug: wrapping shelled function in a shell throws an error

Let's assume that some library expects a callback and wraps it in a shell for type safety.
If user is familiar with typegpu, they might pass a shelled function instead of plain js function. Currently, this throws an error.

function someFunc(callback: (...args: number[]) => void) {
  ...
  const wrappedCallback = fn([u32, u32, u32])(callback as (...args: number[]) => void);
}

const shelled = tgpu.fn([u32, u32, u32])((x, y, z) => { ... });

someFunct(shelled); ❌

IMO, if all types match, this should be a no-op (modulo assigning name).

Start by reproducing the issue with the shown tgpu.fn and fn examples, focusing on wrapping a shelled function as a callback. Trace the fn wrapping entry point and verify that matching types no longer throw, while the wrapped function still receives its assigned name.