Bring the customers your migration missed into Business Central

**Objective:** Find active Dynamics GP customers that do not exist in Business Central and create them in BC after the user confirms, for customer `{customer-id}` or, if that is empty, every active GP customer, creating at most `{max-creates}` customers (default 25).

**Step 1: Read the GP customers**

Call `dynamics-gp-get-rm-customer` with `inactive` set to false, and with `customer-id` set to `{customer-id}` when it is given.

**Step 2: Find the gaps in BC**

Call `business-central-get-customer` for the same scope and match GP `customer-id` to BC `customer-number`, trimmed and case-insensitive. Keep the GP customers with no match.

Set aside, and do not create, any customer whose trimmed customer-id is longer than 20 characters (the BC limit). Flag, but still offer, any customer whose GP customer-balance is not zero: creating the customer does not bring its open balance across.

**Step 3: Confirm with the user**

Show the list of customers to create (customer-id, customer-name, city, state, customer-balance) and the set-aside list. Ask the user to confirm. Do not create anything until they say yes. If they name a subset, create only that subset.

**Step 4: Create each confirmed customer**

Call `business-central-create-customer` once per customer with:

* number = the trimmed GP customer-id
* display-name = customer-name
* address-line-1 = address-1, city = city, state = state, postal-code = zip
* phone-number = phone-1 as digits only, with any trailing zero-padded extension removed
* email = main-email-address
* credit-limit = credit-limit-amount

If a create fails, report the error for that customer and continue with the rest. Stop after `{max-creates}` creates.

**Step 5: Confirm**

Call `business-central-get-customer` with `customer-number` for each created customer and confirm it exists. Report: created and confirmed, failed with the error, set aside with the reason.

**Rules & Guidelines:**

* `dynamics-gp-get-rm-customer` is on the dynamics-gp server. `business-central-get-customer` and `business-central-create-customer` are on the business-central server.
* `business-central-create-customer` is the ONLY write this prompt may make, and only after Step 3's confirmation. Do NOT call `business-central-update-customer`, `dynamics-gp-rm-customer-add` or `dynamics-gp-rm-customer-update`, and never write to GP.
* If either system has more than one company, ask the user which GP company and which BC company to use before the first call, and pass them as `company`.

**Validation:**

* If nothing is missing, say every active GP customer already exists in BC and stop.
* The create tool cannot set payment terms or the customer posting group. Tell the user to set both in BC for every new customer before posting to it, and list the GP payment-terms-id and customer-class for each so they know what to choose.