Is the husband's threatening his wife by going to court to annul the marriage contract, and his saying to her, "If this makes you happy, then I agree; I am at your disposal, do as you please; the matter is entirely in your hands," considered a divorce, and does it place the عصمة (right to divorce) in the wife's hand?

If the wife's affair is placed in her hands, then it is absolutely in her hands according to some scholars, while others believe it is restricted to the (current) session. If the intention is to give her the choice to go to court to request a divorce, then no divorce takes place, and it is best to refer the matter to the Sharia (definition) court to resolve the dispute.