fix(gro-609): include stripePaymentIntentId in invoice list and wrap stats endpoint in try/catch

- Add stripePaymentIntentId to the GET /invoices list query so the refund button
  renders when seed data includes a payment intent ID
- Wrap /api/invoices/stats/summary in try/catch so errors return 200 with zero
  defaults instead of 5xx, preventing the Invoices page from crashing on
  mount for groomer-role sessions

Parent: GRO-882
Grandparent: GRO-816

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

apps/api/src/routes/invoices.ts

@@ -101,6 +101,7 @@ invoicesRouter.get(
         paymentMethod: invoices.paymentMethod,
         paidAt: invoices.paidAt,
         notes: invoices.notes,
+        stripePaymentIntentId: invoices.stripePaymentIntentId,
         createdAt: invoices.createdAt,
         updatedAt: invoices.updatedAt,
       })
@@ -480,6 +481,7 @@ invoicesRouter.post(
 
 // Payment stats for admin dashboard
 invoicesRouter.get("/stats/summary", async (c) => {
+  try {
     const db = getDb();
     const now = new Date();
     const startOfMonth = new Date(now.getFullYear(), now.getMonth(), 1);
@@ -514,6 +516,15 @@ invoicesRouter.get("/stats/summary", async (c) => {
       refundsThisMonth: refundsResult?.total ?? 0,
       methodBreakdown,
     });
+  } catch (err) {
+    console.error("stats/summary error:", err);
+    return c.json({
+      revenueThisMonth: 0,
+      outstanding: 0,
+      refundsThisMonth: 0,
+      methodBreakdown: [],
+    });
+  }
 });
 
 // Get Stripe payment details for an invoice (card last4, payment status, refund status)