For a related feature, also see Tag folders (in tag pane). It requests adding folders in the tag pane to allow organizing at the tag pane level (vs from inside each note). I think both could be implemented and could be complimentary.
If Tag Folders happened to be implemented first then they could be used to organize the dashed workaround suggested by @maartin. For example, #project-checklist could be placed in a “Project” tag folder.