Requested feature overview description.
When a new tag is created whose name matches the pattern *_(disambiguation), change its category to invalid. Prevent tags which match that pattern from having their category changed to anything but invalid.
Why would it be useful?
Disambiguating a tag is currently a somewhat fraught process. A two-step BUR is required, one to actually make the alias and a second to change the category of the target. Sometimes this can backfire due to the non-deterministic nature of BURs, requiring manual intervention: see topic #33446. I'm not sure exactly how the current system enforcing the lore category on *_(lore) tags works but it might be possible to reuse some of that. There will never be a valid reason to create a tag matching this pattern.
Vandalism potential is minimal since there's already nothing stopping people from applying disambiguation tags manually, this just gives them a different colour.
What part(s) of the site page(s) are affected?
Post editing, aliases/implications/BURs.