Find BigCommerce customers missing from Salesforce

**Objective:** Find BigCommerce customers created in the last `{lookback-days}` days (default 30) that do not exist in Salesforce, checking at most `{max-customers}` customers (default 25).

**Step 1: Recent customers in BigCommerce**

Call `bigcommerce-get-customer` (BigCommerce server) with `date-created.from` set to the start of the window and `max-records` set to the limit. Keep `id`, `name`, `email`, `company` and `phone`.

**Step 2: Check each one in Salesforce**

For each customer with an `email`, call `salesforce-get-contact` (Salesforce server) with that `email`. If nothing matches, call `salesforce-get-lead` with the same `email`. Mark the customer as in-contacts, in-leads or missing. Customers with no email are listed separately as unmatchable.

**Step 3: Report**

First a count line: checked, in contacts, in leads, missing, no email. Then a table of the missing customers with `name`, `email`, `company`, `phone` and the BigCommerce `date-created`.

**Rules & Guidelines:**

* `bigcommerce-get-customer` is on the BigCommerce server; `salesforce-get-contact` and `salesforce-get-lead` are on the Salesforce server.
* Read-only. Do not call `salesforce-add-lead`, `salesforce-add-contact` or `bigcommerce-customer-update`; the user can ask for leads to be created afterwards.
* Compare emails case-insensitively.

**Validation:**

* If BigCommerce returns no customers in the window, say so and stop.
* If the limit was reached, say the list may be incomplete.