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/lib/utils/otp.ts

@@ -0,0 +1,19 @@
+/** Keep only ASCII digits (maps Persian/Arabic numerals). */
+export function normalizeOtpInput(value: string): string {
+  const persian = "۰۱۲۳۴۵۶۷۸۹";
+  const arabic = "٠١٢٣٤٥٦٧٨٩";
+  let out = "";
+  for (const ch of value) {
+    if (ch >= "0" && ch <= "9") out += ch;
+    else {
+      const pi = persian.indexOf(ch);
+      if (pi >= 0) {
+        out += String(pi);
+        continue;
+      }
+      const ai = arabic.indexOf(ch);
+      if (ai >= 0) out += String(ai);
+    }
+  }
+  return out.slice(0, 6);
+}