Find Shopify refunds missing from Dynamics GP

**Objective:** For Shopify refunds created in the last `{lookback-days}` days (default 14), find the matching Dynamics GP credit memo or return, and report the refunds that are missing from GP or whose amounts differ.

**Step 1: Read the Shopify refunds**

Call `shopify-get-refund` (Shopify server) with `created-at.from` = today minus `{lookback-days}` days. Keep `refund-id`, `order-name`, `customer-email`, `created-at` and `order-id`. For each refund call `shopify-get-refund-line` (Shopify server) with `order-refund-id` = the `refund-id`, and total `subtotal` plus `total-tax` to get the refunded amount. Keep each line's `sku` and `quantity`.

**Step 2: Read Dynamics GP credit documents**

Call `dynamics-gp-get-rm-trx` (Dynamics GP server) with `document-date.from` = the same start date and `document-type` = credit memo, passing `company` = `{gp-company}` when it is given. Also call `dynamics-gp-get-rm-sales-trx` (Dynamics GP server) with the same date range and `sop-type` = return. Neither tool filters on the PO number, so match locally: a GP document matches a refund when its `customer-po-number` equals the refund's `order-name` (with or without the leading #).

**Step 3: Report**

1. Refunds with no GP credit: order name, refund date, amount, customer email, and the SKUs refunded.
2. Amount mismatches: order name, Shopify refunded amount, GP `document-amount`, difference, GP `document-number` or `sop-number`.
3. GP credit documents in the range whose PO number looks like a Shopify order name but matched no refund.
4. The count of refunds that matched cleanly.

**Rules & Guidelines:**

* Tools whose names start with shopify are on the Shopify server; tools whose names start with dynamics-gp are on the Dynamics GP server.
* This is read-only. Do NOT call `dynamics-gp-rm-trx-add`, `dynamics-gp-rm-sales-trx-add` or `dynamics-gp-srv-rma-add`.

**Validation:**

* If Shopify returns no refunds, say so and stop.
* A refund may be split across several GP documents; if two or more GP documents share the order name, compare their sum.
* If GP returns more documents than the default page, raise `max-records` rather than reporting refunds as missing.