Keep overdue accounts out of promotional sends

**Objective:** Put Business Central customers with an overdue balance of at least `{min-balance-due}` (default 0.01) into the static Mailchimp segment `{segment-name}` on the audience `{list-name}`. Use the Business Central company `{company}`; if it is empty, omit the `company` filter.

**Step 1: Overdue customers**

Call `business-central-get-customer` with `balance-due.min` set to the minimum. Keep customer-number, name, email, balance-due and salesperson-code. Drop customers with an empty email.

**Step 2: Find the audience and segment**

Call `mailchimp-get-list` with `name` set to `{list-name}` and take its list-id. Then call `mailchimp-get-segment` with `list-id` set to it and `name` set to `{segment-name}`. If the segment is not found, or its type is not static, stop and say so: this prompt does not create segments and cannot add members to a saved (conditional) segment.

**Step 3: Which customers can be tagged**

For each email, call `mailchimp-get-segment-member` with `segment-id` set and `email` set to it, and skip anyone already in the segment. For the rest, call `mailchimp-get-list-member` with `email` set to it and `list-name` set to `{list-name}`. Anyone who is not an audience member cannot be added to a segment; list them separately.

**Step 4: Confirm**

Show a table of the customers to add (customer-number, name, email, balance-due) and ask the user to confirm. Do not continue without an explicit yes.

**Step 5: Add and confirm**

For each confirmed customer, call `mailchimp-add-segment-member` once with `segment-id`, `list-id` and `email-address`. Then call `mailchimp-get-segment-member` with `segment-id` set and report which adds are confirmed and which failed.

**Rules & Guidelines:**

* `business-central-get-customer` is on the business-central server. `mailchimp-get-list`, `mailchimp-get-segment`, `mailchimp-get-segment-member`, `mailchimp-get-list-member` and `mailchimp-add-segment-member` are on the mailchimp server.
* `mailchimp-add-segment-member` is the only write this prompt may make. Do NOT call `mailchimp-add-list-member` or `mailchimp-update-list-member`, and do NOT call any business-central create or update tool.
* This prompt only adds to the segment. It never removes customers who have since paid; say so in the report.

**Validation:**

* If no customers are overdue, say so and stop.
* Match emails case-insensitively after trimming spaces.
* If the audience name matches more than one list, list them and stop.