* feat(cli): billing top-up becomes add-credits, top-up stays as an alias
* fix(cli): keep the skills manifest and core-skills test in step with add-credits
* revert: leave the core-skills test to its own PR
* feat(cli): billing shows the price and pays from the terminal on Enter
* fix(cli): the top-up page opens at the credit packs
* test(cli): billing tests cover the checkout offer with no terminal
* fix(cli): the purchase wait runs while Press Enter is open