Know if your last Mailchimp campaign beat your usual results

**Objective:** Review how the Mailchimp campaign `{campaign-title}` performed, compare it with the previous {compare-count} campaigns sent to the same audience (default 5), and explain what drove the result.

**Step 1: Resolve the campaign**

Call `mailchimp-get-campaign` with `title` set to the campaign title. If nothing matches, retry with `title.contains`. If more than one campaign matches, list them with title, send-date and status, and stop. If the campaign's status is not `sent`, say it has not been sent yet and stop. Keep its campaign-id, list-name and send-date.

**Step 2: Read the results**

* Call `mailchimp-get-report` with `campaign-id` for opens, clicks, bounces, unsubscribes, abuse reports and total revenue.
* Call `mailchimp-get-campaign-click` with `campaign-id` to see which links drew the clicks.
* Call `mailchimp-get-campaign-recipient` with `campaign-id` and `status` set to `hard`, then again with `soft`, to see who bounced.
* Call `mailchimp-get-campaign-unsubscribe` with `campaign-id` and group the unsubscribe reasons.

**Step 3: Build the baseline**

Call `mailchimp-get-report` with `list-name` set to the campaign's list and `send-date.to` set to the day before this campaign's send-date. Take the most recent campaigns up to the compare count, and average their open rate, click rate, hard bounce rate (hard-bounces / emails-sent) and unsubscribe rate (unsubscribed / emails-sent).

**Step 4: Report**

* A one-line verdict: better than, in line with, or worse than recent campaigns.
* A table with one row per metric (emails sent, open rate, click rate, hard bounce rate, soft bounces, unsubscribe rate, abuse reports, revenue) and columns for this campaign, the recent average and the difference.
* The top 5 links by unique clicks.
* Unsubscribe reasons, grouped, with counts.
* 2 to 4 observations, each tied to a number above.

**Rules & Guidelines:**

* Read only. Do not call `mailchimp-add-list-member`, `mailchimp-update-list-member`, `mailchimp-add-segment-member`, `mailchimp-add-customer`, `mailchimp-update-customer`, `mailchimp-update-product`, `mailchimp-update-order`, `mailchimp-replicate-campaign`, `mailchimp-start-automation` or `mailchimp-pause-automation`.
* Rates are returned as fractions (0.25 means 25%). Show them as percentages.
* Treat any abuse report, a hard bounce rate above 2%, or an unsubscribe rate above 0.5% as worth calling out on its own, whatever the other numbers say.
* Show at most 5 individual email addresses from the bounce and unsubscribe lists unless the user asks for more.

**Validation:**

* If there are no earlier campaigns to the same list, report this campaign alone and say there is no baseline.
* If `mailchimp-get-report` returns nothing for a sent campaign, say the report is not available yet and stop.