fix(reconcile): connect mongoose before querying members

Route was the only DB-using endpoint that didn't call connectDB(); other
routes warm the connection incidentally, but on a freshly-booted container
with no SLACK_BOT_TOKEN the slack-joins plugin skips and nothing else
opens the pool — first reconcile request hung 10s on buffered Member.find()
and returned 500.

server/api/internal/reconcile-payments.post.js

@@ -9,6 +9,7 @@
 import Member from '../../models/member.js'
 import Payment from '../../models/payment.js'
 import { listHelcimCustomerTransactions } from '../../utils/helcim.js'
+import { connectDB } from '../../utils/mongoose.js'
 import { upsertPaymentFromHelcim } from '../../utils/payments.js'
 
 // Same filter upsertPaymentFromHelcim applies — keep dry-run summary in sync.
@@ -51,6 +52,8 @@ export default defineEventHandler(async (event) => {
 
   const apply = getQuery(event).apply !== 'false'
 
+  await connectDB()
+
   const members = await Member.find(
     { helcimCustomerId: { $exists: true, $ne: null } },
     { _id: 1, email: 1, name: 1, helcimCustomerId: 1, helcimSubscriptionId: 1, billingCadence: 1 }