fix(GRO-890): populate stripePaymentIntentId on all paid seed invoices

All paid invoices created by the seed script now get a deterministic
stripePaymentIntentId of the form pi_test_seed_NNNNNN, unblocking the
refund button conditional in Invoices.tsx:514 during UAT.

Pending/draft invoices retain null as before.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/src/seed.ts

@@ -883,6 +883,7 @@ async function seed() {
   let appointmentCount = 0;
   let invoiceCount = 0;
   let visitLogCount = 0;
+  let paidInvoiceCounter = 0;
 
   // Process in batches per client to keep memory manageable
   const apptBatchSize = 100;
@@ -977,6 +978,10 @@ async function seed() {
 
         const invoiceStatus = rand() < 0.95 ? "paid" as const : "pending" as const;
         const paidAt = invoiceStatus === "paid" ? new Date(endTime.getTime() + randInt(5, 30) * 60 * 1000) : null;
+        paidInvoiceCounter++;
+        const stripePaymentIntentId = invoiceStatus === "paid"
+          ? `pi_test_seed_${String(paidInvoiceCounter).padStart(6, "0")}`
+          : null;
 
         invoiceBatch.push({
           id: invoiceId,
@@ -989,6 +994,7 @@ async function seed() {
           status: invoiceStatus,
           paymentMethod: invoiceStatus === "paid" ? pick(["cash", "card", "card", "card", "check"]) as "cash" | "card" | "check" : null,
           paidAt,
+          stripePaymentIntentId,
           notes: rand() < 0.05 ? "Added extra service at checkout" : null,
         });
 
@@ -1092,13 +1098,16 @@ async function seed() {
       const taxCents = Math.round(effectivePrice * 0.08);
       const totalCents = effectivePrice + taxCents + tipCents;
       const paidAt = new Date(endTime.getTime() + randInt(5, 30) * 60 * 1000);
+      paidInvoiceCounter++;
 
       invoiceBatch.push({
         id: invoiceId, appointmentId: apptId, clientId,
         subtotalCents: effectivePrice, taxCents, tipCents, totalCents,
         status: "paid" as const,
         paymentMethod: pick(["cash", "card", "card", "card", "check"]) as "cash" | "card" | "check",
-        paidAt, notes: null,
+        paidAt,
+        stripePaymentIntentId: `pi_test_seed_${String(paidInvoiceCounter).padStart(6, "0")}`,
+        notes: null,
       });
       lineItemBatch.push({
         id: uuid(), invoiceId, description: svc.name, quantity: 1,