Enroll Shopify customers in Drip only with consent

**Objective:** Add the Shopify customer with email `{email}` to the Drip campaign named `{campaign-name}`, but only if their consent allows it.

**Step 1: Check the Shopify customer**

Call `shopify-get-customer` with `email` set to `{email}`. If nothing comes back, say the person is not a Shopify customer and stop. Note accepts-marketing, name, orders-count and total-spent.

**Step 2: Check Drip**

Call `drip-get-subscriber` with `email` set to `{email}`. If the status is unsubscribed, stop and report that the person has opted out in Drip. If accepts-marketing is false in Shopify, stop and report that the customer has not consented, even if they are in Drip.

**Step 3: Find the campaign**

Call `drip-get-campaign` with `name.contains` set to `{campaign-name}`. If more than one matches, list them (name, status, campaign-id) and stop. If none match, say so and stop. Then call `drip-get-campaign-subscriber` with `email` set to `{email}` and `campaign-id` set to that campaign-id; if a row comes back, say they are already enrolled and stop.

**Step 4: Confirm**

Show the customer, their consent, the campaign name and its status, and warn if the campaign status is not active. Ask the user to confirm. Do not continue without a clear yes.

**Step 5: Enroll and verify**

Call `drip-add-subscriber-to-campaign` with `email` set to `{email}` and `campaign_id` set to the campaign-id. Then call `drip-get-campaign-subscriber` again with the same email and campaign-id and report whether the enrollment is now visible.

**Rules & Guidelines:**

* `shopify-get-customer` is on the shopify server; `drip-get-subscriber`, `drip-get-campaign`, `drip-get-campaign-subscriber` and `drip-add-subscriber-to-campaign` are on the drip server.
* `drip-add-subscriber-to-campaign` is the only tool that may write, once, after Step 4.
* Do NOT call `drip-activate-campaign`, `drip-update-subscriber`, `drip-start-subscriber-workflow` or `shopify-update-customer`.

**Validation:**

* Compare emails case-insensitively.
* If the enrollment does not appear on re-read, report that Drip may take a moment to update rather than retrying the write.