feat(orders): implement QA audit fixes — return flow, refund webhook, TS cleanup

Convex backend (AUDIT-5–10):
- schema: add returnLabelUrl, returnTrackingNumber, returnCarrier fields +
  by_return_tracking_number_and_carrier and by_stripe_payment_intent_id indexes
- orders: markReturnReceived now sets status="completed"; add getOrderByPaymentIntent
  and applyReturnAccepted internal helpers
- returnActions: add acceptReturn action — creates Shippo return label (is_return:true),
  persists label data, sends return label email to customer
- stripeActions: handle refund.updated webhook to auto-mark orders refunded via Stripe Dashboard
- shippoWebhook: add getOrderByReturnTracking; applyTrackingUpdate extended with
  isReturnTracking flag (return events use return_tracking_update type, skip delivered transition)
- emails: add sendReturnLabelEmail; fulfillmentActions: createShippingLabel action

Admin UI (AUDIT-1–6):
- OrderActionsBar: full rewrite per authoritative action matrix; remove UpdateStatusDialog;
  add AcceptReturnButton for delivered+returnRequested state
- AcceptReturnButton: new action component matching CreateLabelButton pattern
- FulfilmentCard: add returnLabelUrl prop; show "Return label" row; rename outbound
  label to "Outbound label" when both are present
- statusConfig: add return_accepted to OrderEventType and EVENT_TYPE_LABELS
- orders detail page and all supporting cards/components

Storefront & shared (TS fixes):
- checkout/success, CheckoutErrorState, OrderReviewStep, PaymentStep: replace
  Button as/color/isLoading/variant="flat" with HeroUI v3-compatible props
- ReviewList: isLoading → isPending for HeroUI v3 Button
- packages/utils: add return and completed entries to ORDER_STATUS_LABELS/COLORS

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

apps/storefront/src/components/checkout/state/CheckoutErrorState.tsx

@@ -1,6 +1,7 @@
 "use client";
 
-import { Button, Link } from "@heroui/react";
+import { Button } from "@heroui/react";
+import Link from "next/link";
 
 /**
  * Checkout error state: error message + retry button + back-to-cart link.
@@ -17,17 +18,15 @@ export function CheckoutErrorState({
     <div className="flex flex-col items-center gap-4 py-12 text-center">
       <p className="text-lg font-medium text-danger">{message}</p>
       <div className="flex flex-col gap-2 w-full md:w-auto md:flex-row">
-        <Button color="primary" onPress={onRetry} className="w-full md:w-auto">
+        <Button variant="primary" onPress={onRetry} className="w-full md:w-auto">
           Try again
         </Button>
-        <Button
-          as={Link}
+        <Link
           href="/cart"
-          variant="flat"
-          className="w-full md:w-auto"
+          className="inline-flex items-center justify-center rounded-medium gap-2 px-4 py-2 w-full md:w-auto bg-default-100 hover:bg-default-200 text-foreground font-medium transition-colors"
         >
           Back to cart
-        </Button>
+        </Link>
       </div>
     </div>
   );

apps/storefront/src/components/checkout/steps/OrderReviewStep.tsx

@@ -119,7 +119,7 @@ export function OrderReviewStep({
 
               <div className="flex flex-col gap-2">
                 <Button
-                  color="primary"
+                  variant="primary"
                   className="w-full bg-[#236f6b] font-medium text-white"
                   size="lg"
                   onPress={handleContinue}

apps/storefront/src/components/checkout/steps/PaymentStep.tsx

@@ -80,7 +80,7 @@ export function PaymentStep({
         </Alert>
         <div className="flex flex-col gap-2 md:flex-row">
           <Button
-            color="primary"
+            variant="primary"
             className="w-full bg-[#236f6b] font-medium text-white md:w-auto"
             onPress={initSession}
           >
@@ -147,7 +147,7 @@ function CheckoutForm({
         </Alert>
         <div className="flex flex-col gap-2 md:flex-row">
           <Button
-            color="primary"
+            variant="primary"
             className="w-full bg-[#236f6b] font-medium text-white md:w-auto"
             onPress={onSessionExpired}
           >
@@ -237,12 +237,12 @@ function CheckoutForm({
 
               <div className="flex flex-col gap-2">
                 <Button
-                  color="primary"
+                  variant="primary"
                   className="w-full bg-[#236f6b] font-medium text-white"
                   size="lg"
                   onPress={handleSubmit}
                   isDisabled={isSubmitting || !checkout.canConfirm}
-                  isLoading={isSubmitting}
+                  isPending={isSubmitting}
                 >
                   {isSubmitting ? "Processing…" : `Pay ${total.amount}`}
                 </Button>

apps/storefront/src/components/product-detail/reviews/ReviewList.tsx

@@ -40,7 +40,7 @@ export function ReviewList({ reviews, total, hasMore, isLoading, onLoadMore }: P
                     <Button
                         variant="ghost"
                         onPress={onLoadMore}
-                        isLoading={isLoading}
+                        isPending={isLoading}
                         className="w-full md:w-auto text-[var(--foreground)] border border-[var(--separator)]"
                     >
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