Moving swing-validation to the platform cluster

### Description

Hi,

The `org.netbeans.modules:org-netbeans-modules-swing-validation` module is currently part of the `ide` cluster.

It notably wraps the `ValidationAPI` library. As a NB Platform user I struggled to re-use this module in my application and I thought it would make more sense to have it part of the `platform` cluster. Would that be possible? It seems to only have [platform dependencies](https://github.com/apache/netbeans/blob/master/ide/swing.validation/nbproject/project.xml).

Also, I struggled to understand why it doesn't have any public packages. I had to declare a `impl` dependency to make this work in my application.

Thanks in advance!

### Use case/motivation

I'm the maintainer of a NB Platform application and I found this validation library very useful for UI validation. I would like it to be the recommended way NB Platform users validate UIs.

### Related issues

_No response_

### Are you willing to submit a pull request?

No, I'm afraid that's beyond my level of Netbeans code competency

### Code of Conduct

Yes

Start with ide/swing.validation/nbproject/project.xml and inspect the org-netbeans-modules-swing-validation module's ValidationAPI usage. Determine whether its dependencies support moving it to the platform cluster and which packages should be public for NB Platform consumers. Done requires an agreed outcome for both cluster placement and API exposure.

Written by the indexing model from the issue text.