Point a Shopify B2B company at the right Intacct customer

**Objective:** Make the Shopify B2B company `{company-name}` point at the right Intacct customer through its external ID, creating the Intacct customer (with payment term `{payment-term}` if given) when none exists. Write nothing without the user's confirmation.

**Step 1: Find the Shopify company**

Call `shopify-get-company` with `name` = `{company-name}`, then with `name.contains` if nothing matches. If more than one company matches, list them and stop. Keep `company-id`, `name` and `external-id`.

If `external-id` is set, call `intacct-get-customer` with `customer-id` = that value. If it resolves, report that the company is already linked to that customer and stop.

**Step 2: Find the Intacct customer**

Call `intacct-get-customer` with `customer-name` = the Shopify name, then with `customer-name.contains` if nothing matches.

* One match: propose linking to it. Show its `customer-id`, `customer-name`, `city` and `status`.
* Several: list them and ask the user to pick one, or to create a new customer.
* None: go to Step 3.

**Step 3: Prepare a new Intacct customer (only if needed)**

Gather the details from Shopify: call `shopify-get-company-contact` with `company-id` and `is-main-contact` = true for `customer-email` and `customer-phone`, and `shopify-get-company-location` with `company-name` for `shipping-address-city` and `shipping-address-province`.

Show the user the customer you would create: name and print-as (both the Shopify company name), email, phone, city, state and payment term `{payment-term}` (leave it blank if not given, so Intacct uses its default). Ask for confirmation. Only after a yes, call `intacct-create-customer` once. Leave `customer-id` blank unless the user supplies one. Read the returned `customer-id`.

**Step 4: Write the link in Shopify**

Show the user: Shopify company name, current external-id (if any), and the Intacct customer-id it will be set to. Ask for confirmation. Only after a yes, call `shopify-update-company` once with `company-id` and `external-id` = the Intacct customer-id. The `company-id` must be a Shopify GID; if the value from `shopify-get-company` is numeric, send `gid://shopify/Company/` followed by the number.

**Step 5: Confirm**

Call `shopify-get-company` with `external-id` = the Intacct customer-id and check it returns this company. Report what was created and what was linked.

**Rules & Guidelines:**

* `shopify-get-company`, `shopify-get-company-contact`, `shopify-get-company-location` and `shopify-update-company` are on the shopify server. `intacct-get-customer` and `intacct-create-customer` are on the intacct server.
* The only write tools this prompt may call are `intacct-create-customer` (at most once, only when no customer exists) and `shopify-update-company` (once, only to set `external-id`). Each needs its own confirmation. Do NOT call `intacct-update-customer` or change any other Shopify field.
* If `intacct-create-customer` fails, stop and do not update Shopify.

**Validation:**

* If `external-id` was set but broken (no Intacct customer), show the old value before replacing it and say it will be overwritten.
* If the user declines either confirmation, stop and report what, if anything, was already written.