feat(admin): add pre-registrant alert detectors

server/utils/adminAlerts.js

@@ -116,4 +116,49 @@ export async function detectSuspendedMembers() {
   }
 }
 
+function preRegItem(preReg, sublabel) {
+  return {
+    id: String(preReg._id),
+    label: preReg.name || preReg.email,
+    sublabel,
+    href: '/admin/pre-registrants'
+  }
+}
+
+export async function detectPreRegistrantSelectedNotInvited() {
+  await connectDB()
+  const cutoff = daysAgo(ALERT_THRESHOLDS.PREREG_SELECTED_DAYS)
+  const preRegs = await PreRegistration
+    .find({
+      status: 'selected',
+      updatedAt: { $lte: cutoff }
+    })
+    .select('name email updatedAt')
+    .lean()
+  return {
+    type: 'preregistrant_selected_not_invited',
+    severity: 'attention',
+    title: 'Pre-registrants selected but not invited',
+    items: preRegs.map((p) =>
+      preRegItem(p, `${p.email} — ${daysSince(p.updatedAt)} days selected`)
+    )
+  }
+}
+
+export async function detectPreRegistrantExpired() {
+  await connectDB()
+  const preRegs = await PreRegistration
+    .find({ status: 'expired' })
+    .select('name email updatedAt')
+    .lean()
+  return {
+    type: 'preregistrant_expired',
+    severity: 'attention',
+    title: 'Expired pre-registrant invitations',
+    items: preRegs.map((p) =>
+      preRegItem(p, `${p.email} — expired ${daysSince(p.updatedAt)} days ago`)
+    )
+  }
+}
+
 // Aggregator lands in task 8.