fix: reconcile GoPay steps and phone provider flows

- 吸收 PR #193/#194 后补齐 GoPay 订阅确认步骤注册，保持 GoPay Plus 为订阅确认后进入 OAuth 的 11 步流程。

- 修复手机号接码 provider 合并冲突，恢复 5sim/NexSMS/provider 顺序、复用池、价格阶梯和国家回退逻辑。

- 影响范围：共享步骤定义、background 步骤注册、手机号验证 Step 9、相关单元测试。

background.js

@@ -9906,6 +9906,7 @@ const stepExecutorsByKey = {
   'clear-login-cookies': () => step6Executor.executeStep6(),
   'plus-checkout-create': (state) => plusCheckoutCreateExecutor.executePlusCheckoutCreate(state),
   'plus-checkout-billing': (state) => plusCheckoutBillingExecutor.executePlusCheckoutBilling(state),
+  'gopay-subscription-confirm': (state) => goPayManualConfirmExecutor.executeGoPayManualConfirm(state),
   'paypal-approve': (state) => normalizePlusPaymentMethod(state?.plusPaymentMethod) === PLUS_PAYMENT_METHOD_GOPAY
     ? goPayApproveExecutor.executeGoPayApprove(state)
     : payPalApproveExecutor.executePayPalApprove(state),