Implement `preimage` for `ceil` and `round` functions

> @devanshu0987 it seems like a similar technique could be used for `ceil` -- if you agree I will file a ticket to track

Hi @alamb , I would like to attempt this technique for the following functions

- `ceil` and `round`
- `ceil(x) = 5` -> `(4, 5]`
- `round(x) = 5` -> `[4.5, 5.5)`
- String Prefix Functions
- `left(s, 2) = 'AB'` -> Lexicographically `['AB', 'AC')`
- Not sure if this is already implemented.
- Not sure how complex this will be for Non latin strings etc.

_Originally posted by @devanshu0987 in https://github.com/apache/datafusion/issues/20099#issuecomment-3845736417_