Know who you can email before subscriptions expire

**Objective:** For 2Checkout subscriptions expiring in the next `{days-ahead}` days (default 30), report which owners can receive a renewal email in Constant Contact and how engaged they are.

**Step 1: Find expiring subscriptions in 2Checkout**

Work out today's date and the end date `{days-ahead}` days later. Call `2checkout-get-subscription` with `expiration-date.from` and `expiration-date.to` set to those dates, `status` ACTIVE, and `max-records` 100. Keep `subscription-reference`, `product-name`, `expiration-date` and `end-user-email`.

**Step 2: Look up each owner in Constant Contact**

For each distinct `end-user-email`, call `constant-contact-get-contact` with `email-address` set to it and record `contact-id` and `permission-to-send`. If no contact exists, mark the owner as not reachable through Constant Contact.

**Step 3: Check recent engagement**

For contacts who can receive email, call `constant-contact-get-contact-activity` with `contact-id` and note the most recent activity type and date, or "no recent activity".

**Step 4: Report**

Group owners as: reachable and engaged, reachable but silent, unsubscribed, and not in Constant Contact. Show the subscription reference, product and expiry date for each, sorted soonest first.

**Rules & Guidelines:**

* Tools whose names start with 2checkout belong to the 2checkout server and tools whose names start with constant-contact belong to the Constant Contact server. Both servers must be connected.
* The shared key is the email address: 2checkout `email` / `end-user-email` / `billing-email` against Constant Contact `email-address`. Compare emails case-insensitively after trimming spaces.
* This is read-only. Never call any 2checkout action tool (any 2checkout tool that adds, updates, cancels, refunds, enables or disables) and never call `constant-contact-add-contact`, `constant-contact-update-contact`, `constant-contact-add-contact-note`, `constant-contact-add-contact-list`, `constant-contact-update-contact-list`, `constant-contact-add-contact-tag`, `constant-contact-update-contact-tag`, `constant-contact-add-campaign`, `constant-contact-update-campaign` or `constant-contact-resend-campaign-to-non-openers`.

**Validation:**

* If nothing expires in the window, say so and stop.
* Do not send or resend any campaign; this prompt only reports who could be reached.
* If a subscription has no email, list it as unmatchable.