fix(ux): URL-addressable marketplace tabs, offers error state, nav reset

Next P1 slice from UX_AUDIT_2026-10-09.md:
- Marketplace hub tabs now live in the URL (?tab=...) so refresh, share and
  back/forward keep the tab; unknown values fall back to Browse.
- ListingOffersPanel shows an error state on a relay outage instead of
  returning null (a failure no longer reads as no offers).
- Nav customizer Reset reseeds from DEFAULT_TAB_IDS (4) instead of a
  hardcoded 3, matching MIDDLE_SLOTS.
New marketUi.offers.loadFailed (en/es).

UX_AUDIT_2026-10-09.md

@@ -18,10 +18,16 @@ exploration passes and should be confirmed before acting.
 - Listing detail: "Make an offer" is hidden for logged-out users and for
   fixed-price listings (the Buy button is the single primary CTA there).
 - New `/marketplace-guidelines` page, linked from the marketplace hub.
+- Marketplace hub tabs are now URL-addressable (`?tab=browse|selling|trades|reputation`)
+  — refresh-stable, shareable, and back/forward friendly.
+- `ListingOffersPanel` shows an error state on a relay outage instead of hiding
+  itself (a failure no longer looks like "no offers").
+- Nav customizer Reset now reseeds from `DEFAULT_TAB_IDS` (four tabs) instead of
+  a hardcoded three, matching `MIDDLE_SLOTS`.
 
 Deferred (own passes): the grid "Mark as sold" -> `MarkSoldDialog` change (touches
 reputation publishing and lives in an emoji-bearing file), payment-UX hardening,
-and signed roles/ban lists.
+signed roles/ban lists, and the nav terminology cleanup.
 
 ---
 

src/components/CustomizeNavSheet.tsx

@@ -4,6 +4,7 @@ import { Button } from '@/components/ui/button';
 import {
   useNavPreferences,
   MIDDLE_SLOTS,
+  DEFAULT_TAB_IDS,
   type NavTab,
 } from '@/hooks/useNavPreferences';
 import { useCurrentUser } from '@/hooks/useCurrentUser';
@@ -69,7 +70,7 @@ export function CustomizeNavSheet({ open, onOpenChange }: CustomizeNavSheetProps
   const handleReset = () => {
     reset();
     // reset() writes defaults; reseed draft from the same default source.
-    setDraft(['lab', 'events', 'crews']);
+    setDraft([...DEFAULT_TAB_IDS]);
   };
 
   // Resolve draft ids to tabs for the preview & reorder list.

src/components/ListingOffersPanel.tsx

@@ -62,7 +62,7 @@ function amountLabel(m: MarketplaceOffer, t: TFunc): string {
 export function ListingOffersPanel({ item, isOwner }: { item: MarketplaceItem; isOwner: boolean }) {
   const { t } = useTranslation();
   const { user, metadata } = useCurrentUser();
-  const { data } = useListingOffers({ pubkey: item.pubkey, identifier: item.identifier });
+  const { data, isError } = useListingOffers({ pubkey: item.pubkey, identifier: item.identifier });
   const { respondToOffer, counterOffer } = useOfferActions();
   const { mutateAsync: sendDM } = useSendDirectMessage();
   const { toast } = useToast();
@@ -73,7 +73,13 @@ export function ListingOffersPanel({ item, isOwner }: { item: MarketplaceItem; i
   const [payFor, setPayFor] = useState<OfferThread | null>(null);
   const [paidThreads, setPaidThreads] = useState<Set<string>>(() => new Set());
 
-  if (!user || !data) return null;
+  if (!user) return null;
+  // A relay outage must not look like "no offers" — surface it instead of hiding
+  // the panel entirely.
+  if (isError) {
+    return <p className="text-sm text-muted-foreground">{t('marketUi.offers.loadFailed')}</p>;
+  }
+  if (!data) return null;
 
   const mine = data.threads.filter((t) => t.buyer === user.pubkey || t.seller === user.pubkey);
   if (mine.length === 0) return null;

src/i18n/en.ts

@@ -1779,6 +1779,7 @@ marketUi: {
       open: 'Open',
       noAmount: 'no amount',
       titleOwner: 'Offers ({{count}})',
+      loadFailed: 'Could not load offers. Check your connection and try again.',
       titleBuyer: 'Your negotiations',
       you: 'You',
       them: 'Them',

src/i18n/es.ts

@@ -1779,6 +1779,7 @@ marketUi: {
       open: 'Abierta',
       noAmount: 'sin importe',
       titleOwner: 'Ofertas ({{count}})',
+      loadFailed: 'No se pudieron cargar las ofertas. Comprueba tu conexión e inténtalo de nuevo.',
       titleBuyer: 'Tus negociaciones',
       you: 'Tú',
       them: 'Ellos',

src/pages/MarketplaceHubPage.tsx

@@ -1,5 +1,4 @@
-import { useState } from 'react';
-import { Link } from 'react-router-dom';
+import { Link, useSearchParams } from 'react-router-dom';
 import { Store, Handshake, Star, Package } from 'lucide-react';
 import GearSwapPage from '@/pages/GearSwapPage';
 import TradesPage from '@/pages/TradesPage';
@@ -27,7 +26,16 @@ type TabId = (typeof TABS)[number]['id'];
 export default function MarketplaceHubPage() {
   const { t } = useTranslation();
   const { user } = useCurrentUser();
-  const [tab, setTab] = useState<TabId>('browse');
+  // The active tab lives in the URL (?tab=…) so it survives refresh, is
+  // shareable, and works with back/forward. Unknown values fall back to Browse.
+  const [searchParams, setSearchParams] = useSearchParams();
+  const requested = searchParams.get('tab');
+  const tab: TabId = (TABS.some((entry) => entry.id === requested) ? requested : 'browse') as TabId;
+  const setTab = (id: TabId) => {
+    const next = new URLSearchParams(searchParams);
+    next.set('tab', id);
+    setSearchParams(next, { replace: true });
+  };
 
   return (
     <>