I've taken another look at your mod, and i think everything should be working now. (updated version attached)
What have i changed?:
- Changed the info.json to factorio version 0.15, and changed the version number of the mod.
- I've taken out the item.lua and demo-item.lua, as the copying of item trees is not necessary when creating new recipes for an item, or changing existing ones.
- If you take a look in the productivity-config.lua, you can probably already see what i changed. The allowed recipes are specified in a function not unlike the one i wrote. Then, under the productivity module's limitation value, the name of the function is listed. All i did here is replace the default function with a new one which incorprets the new recipes. (Note that only one string can be listed for each "limitation" value, so adding a new value with only the changed recipes is not possible.) I also added productivity module 2 and 3 to the changed list.
- I've taken a look at the entity.lua, and saw that the only changed value in there (correct me if i'm wrong) was the allowed_effect: "productivity". So i added a table.insert for "productivity". Generally, if you're only changing one value of an entity, item, recipe, or stuff like that, you should use either data.raw..., or insert.table(data.raw...), as copying entire trees is a bit of a rough way of doing it. (And i think that, with copying entire trees, you can run into problems with future updates.)
- In technology.lua, i've added "advanced-electronic-circuit", as that recipe had no way of being activated/revealed before. (enabled was "false", and no tech unlocked it.) I've changed the name to "advanced-electronics-3", as it seems like a logical step up from 2.
- Finally, i've removed the unnecessary names from the locale.cfg. The tech name for electronics is handled automatically, the item names are already defined in the base locale, the new "advanced-(module tier)" recipes have no entity, and you don't need to add empty description categories to the locale.
Another suggestion i have would be to change the technology order of "advanced-electronics-3", and change the icon to the "advanced-electronics-2" icon, but that's just my perfectionism talking...
If you have any questions, please, do ask, especially if you don't understand why i've changed something.
Also, definitely check out the solution robertpaulson posted for the productivity problem, as the method i used is not as compatibility-friendly as that one, even though it works just fine. (I believe that solution adds the recipes directly to the base function, instead of my solution, where i just overwrite the base function entirely. :3)
For the time being, cheers, and best of luck! ;D