fix(build): make admin tree dynamic and catch Supabase fetch errors at build

Two errors were aborting the Gitea build:

1. DYNAMIC_SERVER_USAGE on /admin/settings/square-sync (and any admin page):
   getAdminUser() reads cookies() via next/headers. The admin layout tried
   to prerender statically, so the first child page that hit cookies()
   aborted the build. Added 'export const dynamic = "force-dynamic"' to
   src/app/admin/layout.tsx so the whole admin tree opts out of static
   prerender.

2. Prerender ECONNREFUSED on /indian-river-direct/stops and the sitemap:
   getPublicStopsForBrand / getActiveStopsForSitemap / getBrandSettingsPublic
   fetch NEXT_PUBLIC_SUPABASE_URL at build time. The Gitea runner sets the
   Supabase env vars (so the existing env-var guard passes) but the URL
   is unreachable, so fetch throws ECONNREFUSED and the prerender aborts.
   Wrapped each fetch in try/catch returning [] / {success: false} so the
   prerender completes; runtime behavior is unchanged when the fetch
   succeeds.

Also added force-dynamic to the square-sync page itself as belt-and-braces
in case the layout change doesn't propagate.

src/app/admin/layout.tsx

@@ -8,6 +8,11 @@ import "@/styles/admin-design-system.css";
 import { ToastProvider } from "@/components/admin/Toast";
 import { ToastContainer } from "@/components/admin/ToastContainer";
 
+// Admin layout calls getAdminUser() which reads cookies(). Without this,
+// Next.js tries to prerender the entire /admin/* tree statically and the
+// first page that hits cookies() aborts the build with DYNAMIC_SERVER_USAGE.
+export const dynamic = "force-dynamic";
+
 // Toast provider wrapper component
 function ToastProviderWrapper({ children }: { children: React.ReactNode }) {
   return (

src/app/admin/settings/square-sync/page.tsx

@@ -4,6 +4,10 @@ import { getPaymentSettings } from "@/actions/payments";
 import { getSyncLog, type SyncLogEntry } from "@/actions/square-sync-ui";
 import SquareSyncSettingsClient from "./SquareSyncSettingsClient";
 
+// Uses cookies() via getAdminUser — must be dynamic to avoid the
+// "couldn't be rendered statically" build error.
+export const dynamic = "force-dynamic";
+
 export default async function SquareSyncSettingsPage() {
   const adminUser = await getAdminUser();
   if (!adminUser) redirect("/login");