feat(vendors): auto-verify vendor on first successful payment

When accounts confirms a payment (SENT_FOR_PAYMENT → PAID_DELIVERED),
set Vendor.isVerified = true for the PO's vendor. The field already
exists in the schema (default false); this closes the loop so vendors
who have transacted at least once are marked verified automatically
without manual admin intervention.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

App/pelagia-portal/app/(portal)/payments/actions.ts

@@ -169,6 +169,14 @@ export async function markPaid({
   // Sync product catalog: auto-create new items, upsert per-vendor prices
   await syncProductCatalog(poId, po.lineItems, po.vendorId, session.user.id);
 
+  // Auto-verify the vendor on first successful payment
+  if (po.vendorId) {
+    await db.vendor.update({
+      where: { id: po.vendorId },
+      data: { isVerified: true },
+    });
+  }
+
   const managers = await db.user.findMany({ where: { role: "MANAGER", isActive: true } });
   await notify({ event: "PAYMENT_SENT", po, recipients: [po.submitter, ...managers] });