feat(plans): menu watermark on Free (removed by paid feature)

Guest QR menu shows a "ساخته‌شده با میزی" watermark under the menu unless the café's
plan has the `watermark_removed` feature (Starter+).

- PublicMenuDto gains ShowWatermark; PublicService computes it from
  IsFeatureEnabledForCafeAsync("watermark_removed") for both slug and branch menus.
- Guest menu renders the watermark footer when showWatermark.
- NoOpPlatformCatalogService test double (all features on) for the PublicService
  ctor; QrMenuTests updated.

86 tests pass; dashboard tsc clean.

web/dashboard/src/components/qr/qr-guest-menu.tsx

@@ -65,6 +65,7 @@ export function QrGuestMenu({ code }: QrGuestMenuProps) {
   const [tableOrders, setTableOrders] = useState<GuestOrderRef[]>([]);
   const [submitting, setSubmitting] = useState(false);
   const [menuTheme, setMenuTheme] = useState<CafeTheme | null>(null);
+  const [showWatermark, setShowWatermark] = useState(false);
   const [searchQuery, setSearchQuery] = useState("");
   const [view3dItem, setView3dItem] = useState<QrPublicMenuItem | null>(null);
   const [security, setSecurity] = useState<PublicSecurityConfig | null>(null);
@@ -111,6 +112,7 @@ export function QrGuestMenu({ code }: QrGuestMenuProps) {
         const cats = menu.categories ?? [];
         setCategories(cats);
         setMenuTheme(normalizeCafeTheme(menu.theme ?? undefined));
+        setShowWatermark(menu.showWatermark ?? false);
         setActiveCategory(QR_ALL_CATEGORY_ID);
         if (cats.length === 0) {
           setError(t("emptyMenu"));
@@ -565,6 +567,16 @@ export function QrGuestMenu({ code }: QrGuestMenuProps) {
             view3d: t("view3d"),
           }}
         />
+        {showWatermark ? (
+          <a
+            href="https://meezi.ir"
+            target="_blank"
+            rel="noopener noreferrer"
+            className="flex items-center justify-center gap-1 py-5 text-xs qr-muted opacity-70"
+          >
+            ساخته‌شده با <span className="font-bold">میزی</span>
+          </a>
+        ) : null}
       </div>
       {totalItems > 0 ? (
         <div className="pointer-events-none fixed inset-x-0 bottom-[3.25rem] z-40 mx-auto max-w-md px-3 pb-1">

web/dashboard/src/lib/api/qr-public.ts

@@ -53,6 +53,8 @@ export type QrPublicMenu = {
   slug: string;
   theme?: CafeTheme | null;
   categories: QrPublicMenuCategory[];
+  /** Free plan shows the Meezi watermark under the menu; paid plans hide it. */
+  showWatermark?: boolean;
 };
 
 export type QrCartLine = {