Find invoices that differ between Chargebee and NetSuite

**Objective:** For invoices dated between {date-from} and {date-to}, find invoices missing from NetSuite, missing from Chargebee, or with a different total. Limit to one customer when {customer-email} is given (default: all customers).

**Step 1: Read Chargebee invoices**

If {customer-email} is given, call `chargebee-get-customer` with `email` set to it and take `id`. Then call `chargebee-get-invoice` with `date.from` and `date.to` (and `customer-id` when known). Keep `id`, `po-number`, `customer-id`, `total`, `amount-due`, `status`, `currency-code`.

**Step 2: Read NetSuite invoices**

Call `netsuite-get-invoice` with `date.from` and `date.to` (and `customer` set to the NetSuite customer name when a single customer was requested). Keep `document-number`, `customer-email`, `total`, `unpaid-amount`.

**Step 3: Match and report**

Match a Chargebee invoice to a NetSuite invoice when the Chargebee `id` or `po-number` equals the NetSuite `document-number`; fall back to the same customer email, date and total. Report three lists: in Chargebee only, in NetSuite only, and matched with different totals (show both amounts and the difference). End with counts.

**Rules & Guidelines:**

* Tools whose names start with netsuite are on the netsuite server; tools whose names start with chargebee are on the chargebee server. Both servers must be connected.
* Read-only: never call any NetSuite add or update tool (for example `netsuite-add-invoice`, `netsuite-add-customerpayment`, `netsuite-update-invoice`, `netsuite-update-customer`). Chargebee has no write tools here. Report differences only; never fix them.
* Chargebee draft or voided invoices are expected to be absent from NetSuite; list them separately instead of as errors.

**Validation:**

* If the two systems number invoices differently so nothing matches by number, say so and match on customer email, date and total, marking those as low confidence.
* If either side returns no invoices, report that and stop.