In the tag data entry UI, when I am typing a part of the term (as in issue #1) and getting suggestions, additionally I want to receive information about narrower and broader terms so that I can better understand the term and have the option to choose a more accurate tag.

I want to obtain all the tags from a controlled tag source. The tag server at the best is a REST-based remote terminology server that is able to exchange data in JSON format. Based on the query that has been send to the terminology server, it will reply with a set of suggestions. each suggestion contains a label, a URI, a description, and the source Id (if the server supports more than one terminologies).

When I as a user want to create a new dataset, during metadata entry I have the option to provide free tags. I want to get suggestions from a tag source (terminology server) while typing and then choose from the suggestions obtained from that source.
No free text that is not registered in the tag source should be accepted.

In issue #1, it was enough to store the tag's text as the key, but in a larger setting with multiple terminologies or terminology servers, there is a chance of name conflict in the tags (terms) in different domains. I want to persist the URI of the chosen terms in CKAN, alongside their labels.

When I create a dataset with semantic tags, later when I (or someone else) looks at that dataset, I should be able to get additional data such as description, source, URI, etc. of the tag by hovering over it.