Find the Rillet customers Drip cannot reach

**Objective:** Find the Rillet customers that Drip cannot reach because their email address is not a Drip subscriber, checking emails of type `{email-type}` (default: every type).

**Step 1: Read Rillet customer emails**

Call `rillet-get-customer-emails` (Rillet) once. If `{email-type}` is set, keep only rows with that email-type. Drop blank emails and de-duplicate by lower-cased email.

**Step 2: Check each address in Drip**

For each email, call `drip-get-subscriber` (Drip) with email set to that address. Record one of: missing (no row), active, or unsubscribed (any other status, reported as given).

If there are more than 50 emails, instead call `drip-get-subscriber` (Drip) once with max-records set high enough to cover the list, and match in memory.

**Step 3: Report**

A table of the missing addresses: email, Rillet customer name, customer-id, email-type, country. Below it, a second short table of addresses that exist in Drip but are unsubscribed. End with counts: checked, active in Drip, unsubscribed, missing.

**Rules & Guidelines:**

* The only key shared by the two systems is the email address. Rillet emails come from `rillet-get-customer-emails` (one row per address, with its customer-id and email-type); Drip emails come from the email field of `drip-get-subscriber`. Compare them trimmed and lower-cased. Never match on name alone.
* This prompt is read-only. Do not call `drip-add-subscriber`, `drip-update-subscriber`, `drip-add-subscriber-tag`, `drip-remove-subscriber-tag`, `drip-add-subscriber-to-campaign`, `drip-remove-subscriber-from-campaign`, `drip-remove-subscriber-from-all-campaigns`, `drip-unsubscribe-subscriber`, `drip-start-subscriber-workflow`, `drip-remove-subscriber-from-workflow`, `drip-activate-campaign`, `drip-pause-campaign`, `drip-activate-workflow`, `drip-pause-workflow` on Drip, and do not call any Rillet tool whose name starts with rillet-add, rillet-update, rillet-apply, rillet-unapply, rillet-record, rillet-set or rillet-setup.
* This prompt only reports. To add the missing customers, use the sync-customers-to-drip prompt.

**Validation:**

* If Rillet returns no emails (or none of the requested type), say so and stop.
* A Drip email that differs only by case or surrounding spaces is a match, not a gap.