I've made and tested my https://mods.factorio.com/mod/lo-recipe-combinator

But I had to comment this line in your code to make it work... As you explicitly banned 'assembling-machine' from being placed inside editor.

Please accept this single line minimalist change:
https://github.com/Telkine2018/compaktcircuit/pull/54

I've looked into your code, this "forbidden_prototypes" only affect remote calls and nothing else...

(In fact I don't really understand why you limit this modded combintors from having any type as you have no checks for it's internal sub entities... This "forbidden_prototypes" seems redundant, but, anyway...)

I don't want to allow any kin of assembly machine to be put in a compact processor. Besides your solution does not support packed mode. There are already in the description the steps to support properly any kind of combinators. The example has been updated for Factorio 2.0.

I've tested it on a locally forked version of your mod - I does work in packed mod, I can send you a video or a save file (or you can just try it out yourself on 1.2.3 version of Recipe Combinator).
And it's not really an assembly machine it's speed is set to almost zero - no one would be able to craft anything with it, it's just implemented as assembly machine but can't be used as one.

AND this change won't allow any other assembly-machines inside Compact circuits processor - only ones that are registered with mods specifically with your API - you use that "forbidden_prototypes" solely for other mods' calls and not for actual placing any entity (for that you have a separate check - please review your code).

"There are already in the description the steps to support properly any kind of combinators." - and I've done thouse steps, but to integrate it already. It just can't be placed because of that restriction.

And here is a very small video proof about all that:
https://drive.google.com/drive/folders/1BUuq1wJ23jxwTY9DvNgXJZWYVrUcHCs0?usp=drive_link

that it
- works in packed
- doesn't allow building any real assembly machines (or anything like that)
- and about the code
- plus save file that you can review if you want to

And if you don't mind talking in Telegram or any other messanger and have any other questions - whe can do so, I'll send you my contacts in private message on forum.

I agree with the PR but i was not able to test your mod:
It crashed with the message:

3.577 Error ModManager.cpp:1764: Error in assignID: recipe-category with name 'electronics' does not exist.

Thanks! I will fix that bug shortly.

Fixed and published to version 1.2.4, https://mods.factorio.com/mod/lo-recipe-combinator
Never tested it without Space Age before (which adds 'electronics' category), - now tested.