[Feature Request] Tag Regex System

Tags are used in Ink to send information to the engine that's "running" the story, such as having certain music play at times, or changing the backdrop to a location. Different storytellers have different needs, which is why the Tag system is so adaptable. However, as tags have no set syntax, it can cause errors when the engines run the tag. Maybe a writer forgot to add ".png" to a file name, or they've made a typo and it went unnoticed.
I propose a method of attaching a "tags rule" window, which allows users to add rules to their tags, based on what the tag is. If a tag is then wrong, then it's highlighted as an error, or at least a warning. Tag Rules are stored as dictionaries, with each "tag name" being a key for a regular expression, and stored in a JSON file that is located in the project.
This is something I'd like to work on at some point, but I would like some insight from others on how this sort of feature should be implemented.

No files, tests, or entry points are identified in the issue. Begin by locating how Inky currently parses and displays Ink tags, then determine how a tag-rules window and project-local JSON dictionary could fit; done means agreed behavior for regex validation and clear error or warning feedback.

Written by the indexing model from the issue text.