feat: implement root domain handling for nobat724.com to prevent city filtering

lib/getStateInfo.js

@@ -4,6 +4,9 @@ import { headers } from "next/headers";
 import citiesData from "@/data/city.json";
 import statesData from "@/data/state.json";
 
+import { ROOT_CITY_ID, isRootCity } from "@/lib/rootCity";
+export { ROOT_CITY_ID, isRootCity };
+
 export async function getStateInfo() {
   const headersList = await headers();
 
@@ -20,5 +23,5 @@ export async function getStateInfo() {
     matchedCity &&
     statesData.find((state) => state.id === matchedCity.province_id);
 
-  return { matchedCity, matchedState };
+  return { matchedCity, matchedState, isRoot: isRootCity(matchedCity) };
 }

lib/rootCity.js

@@ -0,0 +1,5 @@
+// رکورد nobat724.com در city.json دامنهٔ ریشه/مخزنِ همهٔ شهرهاست، نه یک شهر.
+// این ماژول pure است (بدون next/headers) تا در client و server هر دو قابل import باشد.
+export const ROOT_CITY_ID = 600;
+
+export const isRootCity = (c) => c != null && Number(c.id) === ROOT_CITY_ID;