fix(billing): Handle nullable bucket skips

Keep the billing null-bucket fallback type-safe so frontend type checks pass
when unsupported plan categories are skipped.

Co-Authored-By: GPT-5.4 <noreply@example.com>
Made-with: Cursor

Author: brendanhsentry

static/gsApp/views/amCheckout/steps/reserveAdditionalVolume.tsx

@@ -43,10 +43,10 @@ export function ReserveAdditionalVolume({
           )
           .some(
             ({category, reserved}) =>
-              getBucket({
+              (getBucket({
                 buckets: activePlan.planCategories[category],
                 events: reserved ?? 0,
-              })?.price > 0
+              })?.price ?? 0) > 0
           )
   );
   const [reserved, setReserved] = useState<Partial<Record<DataCategory, number>>>(

static/gsApp/views/subscriptionPage/utils.tsx

@@ -34,7 +34,8 @@ export function calculateCategorySpend(
   const priceBucket = getBucket({events: categoryInfo.reserved, buckets: slots});
   if (!priceBucket) {
     return {
-      reservedUse: 0,
+      prepaidSpent: 0,
+      onDemandSpent: 0,
       unitPrice: 0,
       onDemandUnitPrice: 0,
       prepaidPrice: 0,