feat: wait for plan selection

[fforbeck]

Add wait() Method to AccountPlan Class

Summary

This PR introduces a new wait() method to the AccountPlan class, which simplifies the process of waiting for a payment plan to be selected. By integrating configurable polling intervals, timeouts, and abort signals, the method abstracts the common logic required in this scenario, making it easier for developers to implement and customize their workflows.

Changes

• New wait() Method:
  • The wait() method repeatedly checks the account's payment plan status at a given interval until:
  • A valid plan is selected.
  • The timeout is reached.
  • The operation is aborted using an AbortSignal.
  • Available options:
  • interval (default: 1000ms): Sets the polling interval.
  • timeout (default: 15 minutes): Defines the maximum wait time.
  • signal: An optional AbortSignal to allow for cancellation.
  • This method improves the developer experience by abstracting the repetitive logic required to wait for a payment plan and offering flexibility through configurable options.

How to Test

1. Run the test suite with npm run build && npm run test.
2. Ensure all existing tests pass.
3. Verify that the new test cases for the wait() method in account.test.js are passing, including tests for:
   • Successful payment plan selection.
   • Timeout errors.
   • Aborted operations.