are you making a new job, or modifying an existing one? an if its an existing one, is it for all kingdoms? as im reading it, just making ALL workers able to craft stuff right?
if you want to change a job, for all kingdoms, it depends on how you do it, you have options!
as you may know the index in jobs tells the game what jobs exist, and points at their descriptions.
in those description files it tells the game where to look for their controller.
now you had already figured out that if you make a custom controller it needs to be declared in your manifest. two options now present themselves(and a third hidden one but i dont know that one)
one: overwrite the existing controller with an override in your manifest with a copied and modified one. its already declared in the original stonehearths manifest so it should be fine (and if not, sommeone will shout this in this thread im sure)
the slightly cleaner way would be to have a copied and modified one (with a different name etc, see my nordlingmod since i also have a different one there than for instance the normal worker) and point from the jobs description to your version instead of the default one. that way, if another mod messes with the controller (see option 3 in a sec) your mod wont fight with those changes but will blatantly ignore them. this may or may not be a good idea.
3rd option i know exists but dont know how to do:
SOMEHOW you are allowed to mix into a .lua, with something called monkey patching. ask paul/dani/bruno/pawel. i havent seen or heared how this eldritch magic works. you probably have to know more lua than holding up a wet finger to see where the wind blows and guessing. (a.k.a my level)
so TLDR: copy the controller from the default game and have a modified version in your mod, overwriting the default one is easiest, but maybe not cleanest option. cleanest is probably making a new one like i did and changing it in the jobs description. but a third mythical option exists but i dont know how.