Deleting a digest makes it sendable again

The dispatch timestamp survived the deletion, so removing a message in Slack
left the digest permanently swallowed. Deleting now rewinds the window to the
newest digest that still stands.

src/lib/admin-settings.ts

@@ -1,6 +1,7 @@
 import { recordAudit } from '~/data/repositories/audit'
 import {
 	clearSetting,
+	findLatestSentRun,
 	findReportRun,
 	markReportRunDeleted,
 	readSettings,
@@ -167,6 +168,14 @@ export async function performDeleteMessage(viewer: Viewer, formData: FormData):
 
 	await markReportRunDeleted(run.id)
 
+	const previous = await findLatestSentRun()
+
+	if (previous) {
+		await writeSetting('slack.lastSentAt', previous.toAt.toISOString())
+	} else {
+		await clearSetting('slack.lastSentAt')
+	}
+
 	await recordAudit({
 		actorId: viewer.id,
 		actorLabel: viewer.email,