fix(gro-609): fix two bugs found by CTO review

1. Refund stats now sum actual refund amounts from refunds table
   instead of incorrectly summing tip_cents from invoices table.

2. Stripe payment_intents.retrieve now expands payment_method
   so card.last4 is correctly available instead of null.

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

apps/api/src/routes/invoices.ts

@@ -495,9 +495,9 @@ invoicesRouter.get("/stats/summary", async (c) => {
     .where(eq(invoices.status, "pending"));
 
   const [refundsResult] = await db
-    .select({ total: sql<number>`coalesce(sum(tip_cents), 0)` })
-    .from(invoices)
-    .where(and(eq(invoices.status, "paid"), sql`${invoices.paidAt} >= ${startOfMonth}`));
+    .select({ total: sql<number>`coalesce(sum(amount_cents), 0)` })
+    .from(refunds)
+    .where(sql`${refunds.createdAt} >= ${startOfMonth}`);
 
   const methodBreakdown = await db
     .select({

apps/api/src/services/payment.ts

@@ -169,7 +169,7 @@ export async function getPaymentIntentDetails(
   const stripe = getStripeClient();
   if (!stripe) return null;
 
-  const pi = await stripe.paymentIntents.retrieve(paymentIntentId);
+  const pi = await stripe.paymentIntents.retrieve(paymentIntentId, { expand: ["payment_method"] });
   const cardLast4 = pi.payment_method
     ? (pi.payment_method as Stripe.PaymentMethod).card?.last4 ?? null
     : null;