fix(email): address Greptile review feedback

- add a sendEmail assertion locking in the payment-failure email's replyTo
- clarify getPersonalEmailFrom() JSDoc so it doesn't overstate replyTo's scope

Author: waleedlatif1

apps/sim/lib/billing/webhooks/invoices.test.ts

@@ -110,6 +110,7 @@ import {
   handleInvoicePaymentSucceeded,
   resetUsageForSubscription,
 } from '@/lib/billing/webhooks/invoices'
+import { sendEmail } from '@/lib/messaging/email/mailer'
 
 interface SelectResponse {
   limitResult?: unknown
@@ -195,6 +196,49 @@ describe('invoice billing recovery', () => {
     expect(mockUnblockOrgMembers).not.toHaveBeenCalled()
   })
 
+  it('sends the payment-failure email with the shared help inbox as reply-to', async () => {
+    queueSelectResponse({
+      limitResult: [
+        {
+          id: 'sub-db-1',
+          plan: 'team_8000',
+          referenceId: 'org-1',
+          stripeSubscriptionId: 'sub_stripe_1',
+        },
+      ],
+    })
+    queueSelectResponse({
+      whereResult: [{ userId: 'owner-1', role: 'owner' }],
+    })
+    queueSelectResponse({
+      whereResult: [{ email: 'owner@sim.test', name: 'Owner' }],
+    })
+
+    await handleInvoicePaymentFailed(
+      createInvoiceEvent('invoice.payment_failed', {
+        amount_due: 3582,
+        attempt_count: 1,
+        customer: 'cus_123',
+        customer_email: 'owner@sim.test',
+        hosted_invoice_url: 'https://stripe.test/invoices/in_123',
+        id: 'in_123',
+        metadata: {
+          billingPeriod: '2026-04',
+          subscriptionId: 'sub_stripe_1',
+          type: 'overage_threshold_billing_org',
+        },
+      })
+    )
+
+    expect(sendEmail).toHaveBeenCalledWith(
+      expect.objectContaining({
+        to: 'owner@sim.test',
+        from: 'billing@sim.test',
+        replyTo: 'help@sim.test',
+      })
+    )
+  })
+
   it('unblocks org members when the matching metadata-backed invoice payment succeeds', async () => {
     queueSelectResponse({
       limitResult: [

apps/sim/lib/messaging/email/utils.ts

@@ -35,8 +35,8 @@ export function extractEmailFromAddress(fromAddress: string): string | undefined
 }
 
 /**
- * Get the personal email from address, for the "from" header only.
- * Reply-to for these emails should come from `getHelpEmailAddress()`, not this value.
+ * Get the personal email from address and reply-to. Lifecycle and billing notification
+ * emails should use `getHelpEmailAddress()` for reply-to instead of the value returned here.
  */
 export function getPersonalEmailFrom(): { from: string; replyTo: string | undefined } {
   const personalFrom = env.PERSONAL_EMAIL_FROM