[FEATURE_REQUEST] Add events when importing and saving character cards/json

[JasonLWalker]

Have you searched for similar requests?

Yes

Is your feature request related to a problem? If so, please describe.

It would be good to have some sort of events that fire when a character is being imported or saved/exported. This would allow plugin developers to add additional import/export types and handlers that could listen for, intercept and handle these new types without having to modify the main SillyTavern source code.

Describe the solution you'd like

a slight modification to /src/endpoints/characters.js would allow the importFromPng, importFromYaml, and importFromJson to fire events that could then be consumed by plugins. If a plugin handles the event, then it could indicate so, and further plugins could then ignore the event.

This could also allow the existing handling of special cases such as CHUB, JanitorAi, and Pygmalion to be moved to plugins to make it easier to maintain them, and additional import/export modules (such as NovelAI/HoloAI) could be more easily build by third-party developers.

I'm looking at building a NovelAI importer for 1.12.0, and would be willing to provide a PR to implement all this if I get to it before someone else does.

Describe alternatives you've considered

No response

Additional context

No response

Priority

Medium (Would be very useful)

Are you willing to test this on staging/unstable branch if this is implemented?

Yes