fix(catalog): stabilise hook order in CatalogPurchaseWidgetView

React reported "Rendered more hooks than during the previous render"
when CatalogPurchaseWidgetView transitioned from currentOffer=null to
a real offer: hook count jumped from 22 to 23 because the
useMemo/useEffect block for the builders-club placement state sat
*below* the `if(!currentOffer) return null` early-return on line 140.
On the first render it never ran; on the next render (offer loaded)
it did, and React's hook-call tracker flagged the divergence and
unmounted the component via the error boundary.

Fix: move the three builders-club hooks (useMemo builderPlaceableStatus,
useMemo buildersClubPlaceOneButtonStyle, useEffect interval) above the
early return. They already short-circuit cleanly when
isBuildersClubPlaceable is false — added a defensive `!currentOffer`
guard on the first useMemo and an explicit `!!currentOffer` clause on
the derived isBuildersClubPlaceable so the .product access stays safe
when offer is null. Behavior unchanged for the loaded-offer path; the
early-render path now runs the hooks but their bodies no-op.

Verification: yarn typecheck clean, yarn test 209/209.

src/components/catalog/views/page/widgets/CatalogPurchaseWidgetView.tsx

@@ -137,15 +137,19 @@ export const CatalogPurchaseWidgetView: FC<CatalogPurchaseWidgetViewProps> = pro
         };
     }, [ purchaseState ]);
 
-    if(!currentOffer) return null;
+    // Builders-club state — derived + hooks MUST run unconditionally on
-
+    // every render so the hook order stays stable even when currentOffer
+    // is null (the `if(!currentOffer) return null` below would otherwise
+    // hide the useMemo/useEffect block from the first render and React
+    // would flag "Rendered more hooks than during the previous render").
     const isBuildersClubOffer = (currentType === CatalogType.BUILDER);
     const isBuildersClubPlaceable = isBuildersClubOffer
+        && !!currentOffer
         && !!currentOffer.product
         && ((currentOffer.product.productType === ProductTypeEnum.FLOOR) || (currentOffer.product.productType === ProductTypeEnum.WALL));
     const builderPlaceableStatus = useMemo(() =>
     {
-        if(!isBuildersClubPlaceable || !getBuilderFurniPlaceableStatus) return BuilderFurniPlaceableStatus.OKAY;
+        if(!isBuildersClubPlaceable || !getBuilderFurniPlaceableStatus || !currentOffer) return BuilderFurniPlaceableStatus.OKAY;
 
         return getBuilderFurniPlaceableStatus(currentOffer);
     }, [ currentOffer, getBuilderFurniPlaceableStatus, isBuildersClubPlaceable, builderPlaceableRefreshTick ]);
@@ -164,6 +168,8 @@ export const CatalogPurchaseWidgetView: FC<CatalogPurchaseWidgetViewProps> = pro
         return () => clearInterval(interval);
     }, [ isBuildersClubPlaceable ]);
 
+    if(!currentOffer) return null;
+
     const PurchaseButton = () =>
     {
         if(isBuildersClubPlaceable)