See where money went across Rillet vendors and accounts

**Objective:** Show where money went between `{from-date}` and `{to-date}`: spend by vendor and by GL account, across bills, card charges and reimbursements, optionally limited to the vendor `{vendor-name}`.

**Step 1: Resolve the vendor (only if one was given)**

If `{vendor-name}` is not empty, call `rillet-get-vendors` and find the vendor whose `name` matches. If more than one matches, list them and stop.

**Step 2: Gather the spend**

* Bills: `rillet-get-bill-lines` with `bill-date.from` = `{from-date}` and `bill-date.to` = `{to-date}` (and `vendor-id` if resolved).
* Card charges: `rillet-get-charge-items` with `charge-date.from` and `charge-date.to` set the same way (and `vendor-id` if resolved).
* Reimbursements: `rillet-get-reimbursement-items` takes no filters. Keep rows whose `reimbursement-date` falls in the period (and the `vendor-id` if resolved).
* Names: `rillet-get-vendors` for vendor names and `rillet-get-accounts` for account names.

**Step 3: Report**

* Top vendors by spend: vendor, bills, charges, reimbursements, total.
* Spend by GL account: account code, account name, total, share of the period.
* Anything notable: a vendor whose spend lands in several unrelated accounts, a single line over 10 percent of the period total, line items with no description.
* Per currency throughout; never add currencies together.

**Rules & Guidelines:**

* This is read-only. Do not call any tool whose name starts with rillet-add-, rillet-update-, rillet-apply-, rillet-unapply-, rillet-record-, rillet-set- or rillet-setup-.
* Use `amount` for spend and report `tax-amount` separately; do not blend them.

**Validation:**

* If the dates are missing or `{from-date}` is after `{to-date}`, ask for them again in YYYY-MM-DD form.
* If nothing is returned, say the period has no recorded spend.