More ergnomic way to specify (named) paramters in signature

would be even nice to refactor such blocks in future so param names and types put together like

```
f.withNames("str", "str_pos").withTpyes("string", "i64")
```

_Originally posted by @comphead in https://github.com/apache/datafusion/pull/18653#discussion_r2524324458_

Start with the signature-building code discussed in PR #18653 and review the current APIs for specifying parameter names and types. Compare them with the proposed withNames and withTypes form, then define the supported ergonomic interface and update its tests so the combined names and types are verified.

Written by the indexing model from the issue text.