feat(dashboard): Next.js 16 merchant panel with offline POS and PWA

Complete merchant dashboard upgrade:

Next.js 16 compatibility:
- Fix params/searchParams typed as Promise<{}> throughout App Router
- Replace middleware.ts with proxy.ts (Next.js 16 convention)
- Remove unused @ts-expect-error directives caught by stricter TS
- Cast dynamic next-intl t() keys to fix TranslateArgs type errors

Offline POS:
- IndexedDB queue (meezi_pos_offline) for orders created while offline
- Zustand sync store tracking queueCount, isSyncing, isOnline
- useOfflineSync hook: auto-syncs on reconnect/visibility-change
- SyncStatusIndicator chip in topbar (amber=offline, blue=syncing)
- submitOrderToApi falls back to local order on network failure
- Local orders skip payment flow; sync on reconnect

PWA (installable):
- @ducanh2912/next-pwa with Workbox runtime caching rules
- Web App Manifest (manifest.ts) — RTL/Farsi, theme #0F6E56
- PWA icons: 192px, 512px, maskable 512px
- next.config.ts replaces next.config.mjs

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

web/dashboard/src/components/queue/queue-display-screen.tsx

@@ -0,0 +1,90 @@
+"use client";
+
+import { useSearchParams } from "next/navigation";
+import { useQuery } from "@tanstack/react-query";
+import { useTranslations, useLocale } from "next-intl";
+import { Link } from "@/i18n/routing";
+import { apiGet } from "@/lib/api/client";
+import type { QueueBoard } from "@/lib/api/types";
+import { useAuthStore } from "@/lib/stores/auth.store";
+import { formatNumber } from "@/lib/format";
+
+export function QueueDisplayScreen() {
+  const t = useTranslations("queue");
+  const locale = useLocale();
+  const numberLocale = locale === "en" ? "en-US" : "fa-IR";
+  const cafeId = useAuthStore((s) => s.user?.cafeId);
+  const searchParams = useSearchParams();
+  const branchId = searchParams.get("branchId");
+  const branchQuery = branchId ? `?branchId=${encodeURIComponent(branchId)}` : "";
+
+  const { data: board } = useQuery({
+    queryKey: ["queue-today", cafeId, branchId, "display"],
+    queryFn: () => apiGet<QueueBoard>(`/api/cafes/${cafeId}/queue/today${branchQuery}`),
+    enabled: !!cafeId,
+    refetchInterval: 5_000,
+  });
+
+  const waiting = board?.tickets.filter((x) => x.status === "Waiting") ?? [];
+  const nowServing = board?.nowServing;
+
+  return (
+    <div className="flex min-h-svh flex-col bg-neutral-950 text-white">
+      <div className="flex items-center justify-between border-b border-white/10 px-6 py-3">
+        <p className="text-sm font-medium uppercase tracking-[0.12em] text-white/60">
+          {t("title")} · {t("displayMode")}
+        </p>
+        <Link
+          href="/queue"
+          className="text-xs text-white/50 underline-offset-2 hover:text-white hover:underline"
+        >
+          {t("exitDisplay")}
+        </Link>
+      </div>
+
+      <div className="flex flex-1 flex-col items-center justify-center gap-10 px-6 py-8">
+        <div className="text-center">
+          <p className="text-lg font-medium uppercase tracking-[0.14em] text-amber-400/90">
+            {t("nowServing")}
+          </p>
+          <p className="mt-2 text-[min(28vw,12rem)] font-bold tabular-nums leading-none text-white">
+            {nowServing != null ? formatNumber(nowServing, numberLocale) : "—"}
+          </p>
+        </div>
+
+        <div className="grid w-full max-w-4xl gap-6 sm:grid-cols-2">
+          <div className="rounded-2xl border border-white/10 bg-white/5 px-6 py-5 text-center">
+            <p className="text-xs uppercase tracking-wide text-white/50">{t("lastIssued")}</p>
+            <p className="mt-2 text-4xl font-semibold tabular-nums">
+              {formatNumber(board?.lastIssued ?? 0, numberLocale)}
+            </p>
+          </div>
+          <div className="rounded-2xl border border-white/10 bg-white/5 px-6 py-5 text-center">
+            <p className="text-xs uppercase tracking-wide text-white/50">{t("displayWaitingLabel")}</p>
+            <p className="mt-2 text-4xl font-semibold tabular-nums text-amber-300">
+              {formatNumber(board?.waitingCount ?? 0, numberLocale)}
+            </p>
+          </div>
+        </div>
+
+        {waiting.length > 0 ? (
+          <div className="w-full max-w-3xl">
+            <p className="mb-3 text-center text-xs uppercase tracking-wide text-white/40">
+              {t("displayUpNext")}
+            </p>
+            <div className="flex flex-wrap justify-center gap-3">
+              {waiting.slice(0, 12).map((ticket) => (
+                <span
+                  key={ticket.id}
+                  className="rounded-xl border border-amber-500/30 bg-amber-500/10 px-5 py-3 text-2xl font-bold tabular-nums"
+                >
+                  {formatNumber(ticket.number, numberLocale)}
+                </span>
+              ))}
+            </div>
+          </div>
+        ) : null}
+      </div>
+    </div>
+  );
+}