This seems to be how Botania ties into the vanilla enchanting menu if I'm reading it right?
https://github.com/VazkiiMods/Botania/blob/1.18.x/Fabric/src/main/java/vazkii/botania/fabric/mixin/FabricMixinEnchantmentMenu.java

An implementation like this is easy, but that's not the point.
Fabric (to my knowledge) lacks a standardized method of registering modded enchantment table boosters (or whatever you want to call them). So me manually adding support would require me to do this for every mod that adds new bookshelves of any kind, and that I won't do.
So maybe I can come up with a clever solution for this issue in the future, or Fabric simple adds support, but for now you'll have to stick to using vanilla bookshelves.
And btw, I'll make the bookshelf detected more lax in the next update.

I'd really like to have this as well, especially since it works on Forge out of the box. Unfortunately Fabric is extremely limiting in these cases, so I'll have to see that I implement special compat when I get back to this mod.

You can just check how botania itself does it regarding the vanilla crafting table.

Can't you just check if the surrounding blocks have enchanting power?