Add missing WooCommerce customers to Drip without resubscribing anyone

**Objective:** Add WooCommerce customers created in the last `{lookback-days}` days (default 7) to Drip if Drip does not have them yet, tagging each with `{tag}` when a tag is given.

**Step 1: List recent WooCommerce customers**

Call `woocommerce-get-customer` with `created-date.from` set to today minus `{lookback-days}` days and `max-records` set to 200. Skip customers with a blank email.

**Step 2: Find who Drip is missing**

For each customer, call `drip-get-subscriber` with `email` set to the customer's email. Keep only the customers where nothing comes back. Anyone Drip already has, whatever their status, is left alone.

**Step 3: Confirm**

Show a table of the customers to add: email, first name, last name, billing country, WooCommerce created date. Say how many were already in Drip and how many of those are unsubscribed. Remind the user that adding people to Drip should only happen for customers who agreed to marketing, since WooCommerce does not record that consent here. Ask the user to confirm the list, or to name people to leave out. Do not continue without a clear yes.

**Step 4: Add the confirmed customers**

For each confirmed customer, call `drip-add-subscriber` once with `email`, `first_name`, `last_name` and `country` (the WooCommerce billing country) from the customer record, plus `tags` set to `{tag}` if a tag was given. Leave `eu_consent` and `status` unset.

**Step 5: Verify and report**

Call `drip-get-subscriber` with `email` for each person added and confirm they now exist. Report added, failed (with the error), and skipped (already in Drip).

**Rules & Guidelines:**

* Tools whose names start with drip- are on the drip server; tools whose names start with woocommerce- are on the woocommerce server. Both servers must be connected.
* Match people across the two systems by email, compared case-insensitively with surrounding spaces removed. Drip uses `email`; WooCommerce uses `email` on customers and `customer-email` on orders, order lines and refunds.
* Compute dates as today minus the stated number of days and pass them as YYYY-MM-DD.
* The only write allowed is `drip-add-subscriber`, once per confirmed customer, after the user confirms in Step 3.
* Never call `drip-add-subscriber` for an email Drip already has: Drip updates the existing person instead, which could resubscribe someone who opted out.
* Do not call `drip-update-subscriber`, `drip-add-subscriber-tag` or `drip-add-subscriber-to-campaign`.
* Make no changes in WooCommerce. Do not call `woocommerce-add-customer`, `woocommerce-update-customer`, `woocommerce-update-order`, `woocommerce-add-order-note`, `woocommerce-add-coupon` or `woocommerce-add-refund`.

**Validation:**

* If no customers were created in the period, or Drip already has all of them, say so and stop without writing anything.
* If an add fails, report it and carry on with the rest; do not retry more than once.
* If a WooCommerce name field is blank, leave the matching Drip field unset rather than inventing a value.