See a customer's balance and email engagement together

**Objective:** Build one profile for Dynamics SL customer `{customer}` that shows their account position (balance, aging, recent orders) next to their email engagement in Constant Contact over the last `{lookback-days}` days (default 90).

**Step 1: Identify the customer in Dynamics SL**

Call `dynamics-sl-get-customers` with `customer-id` = `{customer}`. If nothing comes back, call it again with `customer-name.contains` = `{customer}`. If more than one customer matches, list them (id, name, city) and stop so the user can pick.

**Step 2: Account position**

Call `dynamics-sl-get-customer-balances` with the `customer-id` for current balance, the age-balance buckets, credit limit and average days to pay. Then call `dynamics-sl-get-sales-orders` with the `customer-id` and `order-date.from` set to {lookback-days} days ago for recent orders.

**Step 3: Find the contact in Constant Contact**

Take `email-address` from the customer record and call `constant-contact-get-contact` with it as `email-address`. If the SL field holds several addresses, try each. If no contact matches, report the account section, state that the customer has no Constant Contact contact, and stop there.

**Step 4: Email engagement**

With the contact's `contact-id` and `created-date.from` set to {lookback-days} days ago, call `constant-contact-get-campaign-send`, `constant-contact-get-campaign-open`, `constant-contact-get-campaign-click`, `constant-contact-get-campaign-bounce` and `constant-contact-get-campaign-unsubscribe`.

**Step 5: Report**

* **Account** (Dynamics SL): customer id and name, current balance, overdue buckets, credit limit, average days to pay, number and total of orders in the window.
* **Contact** (Constant Contact): contact id, permission-to-send, tags, lists.
* **Engagement**: sends, opens, clicks (with link URLs), bounces, unsubscribes in the window, and the open rate.
* **Read**: two or three sentences on what the combination suggests, such as an engaged customer with an overdue balance, or a large buyer who never opens email.

**Rules & Guidelines:**

* dynamics-sl tools: `dynamics-sl-get-customers`, `dynamics-sl-get-customer-balances`, `dynamics-sl-get-sales-orders`. constant-contact tools: the get-contact and get-campaign-* reads above.
* Read-only. Do not call `constant-contact-update-contact`, `constant-contact-add-contact-note` or any other write tool.
* If the user has named a Dynamics SL company, pass it as `company` on every dynamics-sl call.

**Validation:**

* An engagement tool that returns nothing means zero for that measure, not an error.
* Do not compute an open rate when there were no sends.