Compare BigCommerce stock with PowerGP Online by SKU

**Objective:** For GP company `{company}`, compare store inventory with GP stock for SKU `{sku}`, or for the first 50 products when `{sku}` is empty, using GP site `{location-id}` (default: all sites).

**Step 1: Store stock (bigcommerce server)**

Call `bigcommerce-get-product` filtered by `sku` when given, and `bigcommerce-get-product-variant` the same way to catch variant SKUs. Keep `sku`, `name`, `inventory-level`.

**Step 2: GP stock (powergp-online-ai server)**

For each SKU call `powergp-online-get-itemsitequantities` with `item-number` set to the SKU, `company` set to `{company}`, and `location-id` when given. Keep `quantity-on-hand`, `quantity-on-order`, `location-id`. Sum `quantity-on-hand` across sites if no site was given.

**Step 3: Report**

Table: SKU, name, store inventory-level, GP on hand, difference, GP on order. Sort by largest absolute difference. Flag store stock above GP on hand as oversell risk and GP on hand above store stock as stock not listed online.

**Rules & Guidelines:**

* `powergp-online-*` tools belong to the powergp-online-ai server (Dynamics GP). `bigcommerce-*` tools belong to the bigcommerce server (online store). Both servers and this prompt server must be connected.
* This prompt is read-only. Call only `get` tools. Never call any `bigcommerce-*-add`, `bigcommerce-*-update` or `bigcommerce-*-delete` tool.
* Query only the GP company given in `{company}`; never mix companies.
* Show at most 25 rows per table and say how many more there are.

**Validation:**

* SKU in the store but not in GP: list it as store-only and continue.
* If the store does not track inventory for a product, note that its store figure is not meaningful.
* With no `{sku}`, process at most 50 products and say so.