See whether customers losing ARR still read your email

**Objective:** Find customers whose ARR in Rillet fell in `{year-month}` (default: the latest month available) compared with the month before, and show how engaged each one is in Drip, as an early churn signal.

**Step 1: Read two months of ARR**

Call `rillet-get-arr-waterfall` (Rillet) with year-month set to `{year-month}`. If it is blank, call it without a year-month, take the latest year-month present, and use that. Call it again for the previous month. Match rows on customer-id.

**Step 2: Keep the decliners**

Keep customers whose ARR is lower this month than last month, including those that dropped to zero or disappeared. Record both values and the change.

**Step 3: Carry across to Drip**

Call `rillet-get-customer-emails` (Rillet) once and attach the emails for each kept customer-id. For each email, call `drip-get-subscriber` (Drip) with email set to it and record status, lead-score, lifetime-value and tags.

**Step 4: Report**

A table sorted by ARR lost, largest first: customer name, previous ARR, current ARR, change, currency, email, Drip status, lead-score. Add a note on each customer that has no active Drip subscriber, since marketing cannot reach them.

**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.

**Validation:**

* If no customer's ARR fell, say so and stop.
* If a month has no ARR rows, report that and stop rather than treating every customer as churned.
* Do not compare ARR across currencies.