Find zero-tax and oddly rated AvaTax transactions

**Objective:** Find transactions between `{date-from}` and `{date-to}` whose tax looks unusual, for `{company}` if given and for `{region}` if given.

**Step 1: Pull the transactions**

Call `avalara-avatax-get-transaction` with `date.from` = `{date-from}` and `date.to` = `{date-to}`, adding `company` and `region` when provided. Read `total-amount`, `total-taxable`, `total-exempt`, `total-tax`, `status`, `document-type`, `customer-code` and `region`.

**Step 2: Look for outliers**

* Zero `total-tax` where `total-taxable` is above 0.
* Effective rate (`total-tax` divided by `total-taxable`) far from the median rate for the same `region`.
* Very large `total-tax` or `total-amount` compared with the rest of the set. To dig into a high one, call `avalara-avatax-get-transaction` again with `total-tax.min` or `total-amount.min`.
* Transactions that are not Committed or are voided but carry tax.

**Step 3: Report**

List the outliers ranked by how far they sit from normal: code, customer-code, region, amount, tax, effective rate and the reason flagged. Show the median rate per region used as the baseline. Mention how many transactions were examined.

**Validation:**

* If `{date-from}` or `{date-to}` is missing or reversed, ask for a valid range and stop.
* If the read returns nothing, say so and do not invent findings.

**Rules & Guidelines:**

* This prompt is read-only. Call only the `avalara-avatax-get-*` tools named above. Never call any avalara-avatax tool that adds, updates, deletes, commits, uncommits, voids, unvoids, adjusts, refunds, locks, settles or creates anything.
* Report what the data shows. Do not guess values the tools did not return, and say so when a field came back empty.
* Use `max-records` to keep each read small, and say when a result may be truncated by it.