Attribute validation: Use type-api connection for instant feedback

The design may not happen with "all" files (if this is even possible), but possibly only a subset (say 2-10 files).

Even then, it would be useful for the designer to get some feedback.

We could use the [type-api](https://typeapi.lab.pidconsortium.net/swagger-ui/index.html) for that (although it still has [some issues](https://github.com/FC4E-T4-3/type-api/issues)). The Typed PID Maker does kind of work around that, but does not yet have an endpoint to validate single attributes (but should not be hard to implement).

We can generate JS code that helps in this regard.

There are some limiting considerations to make:

- If we have an empty function which the designer wants to implement later by hand, we can't check anything.
- This could be worked around if a function is provided with input-output-examples for the available documents.
- -> need a function block which can take in/out examples? Sounds like a relatively heavy task / block.
- -> need a JS serialization to process the value
- -> Or we could (detect and) ignore such cases and show a "maybe" result.
- We would need to evaluate how we display which input file may cause an issue and which worked fine.
- -> similar to github CI result list?