Filter by username should search by uid, not by username string

[jake-low]

When using the Filter UI to search for changesets by a particular user...

... the result is to search for users matching that name (by string value), like this:

https://osmcha.org/filters?filters={"users":[{"label":"jake-low","value":"jake-low"}]}

But that has unexpected results when the user has changed their username in the past. It will only show changesets made by the user under their current name, but not show changesets made prior to their most recent name change.

A better solution would be to search by user ID, which does not change. This is also available through the filter UI:

https://osmcha.org/?filters={"uids":[{"label":"8794039","value":"8794039"}]}

But using it is hard, because you have to look up the ID of the user you want to filter for somewhere else (e.g. https://whosthat.osmz.ru/) and then copy/type it in.

There's no indication in the filter UI or in the results list that searching for a user by username may result in some changesets by that user being omitted. And it's a pretty surprising behavior.

A better, less error prone workflow in OSMCha would be nice. Perhaps the User and User ID filter fields could be combined into one field in the UI, which would accept usernames or user IDs and would automatically lookup the ID for users given by name, and filter for that ID.