Add smoke route exercising logger, i18n, and locale display

src/i18n/locales/en/common.json

@@ -371,6 +371,9 @@
         "IFLY_BODY" : "SU5800–SU5949 Aeroflot flights are operated by iFly aircraft and crew.",
         "IFLY_INFO" : "Information on the on-board service is available <a target=\"_blank\" href=\"https://www.aeroflot.ru/ru-en/aeroflot-ifly\">here</a>."
     },
+    "SMOKE": {
+        "HEADING": "Smoke test page"
+    },
     "FLIGHTS-MAP": {
         "TITLE": "Route map",
         "ROUTE": "Find your route",

src/i18n/locales/ru/common.json

@@ -365,6 +365,9 @@
         "WEEK": "Неделя",
         "WEEK_FORMAT-WRONG": "Не соответствует формату ДД.ММ.ГГГГ - ДД.ММ.ГГГГ"
     },
+    "SMOKE": {
+        "HEADING": "Страница проверки"
+    },
     "WARNING":{
         "IFLY_HIGHLIGHT" : "Обратите внимание!",
         "IFLY_BODY" : "Рейсы Аэрофлота с нумерацией SU5800-SU5949 выполняются на самолётах и экипажем авиакомпании iFly.",

src/routes/[lang]/smoke/page.tsx

@@ -0,0 +1,36 @@
+import { useEffect } from "react";
+import { useParams } from "@modern-js/runtime/router";
+import { useTranslation } from "@/i18n/provider";
+import { useLogger } from "@/observability/logger/provider";
+
+/**
+ * Smoke route at /{lang}/smoke.
+ * Exercises the foundation subsystems as a quick integration check:
+ * - Logger: emits an info log on mount
+ * - i18n: renders a translated string (SMOKE.HEADING)
+ * - Locale display: shows the current lang param
+ */
+export default function SmokePage(): JSX.Element {
+  const { lang } = useParams<{ lang: string }>();
+  const { t } = useTranslation();
+  const logger = useLogger();
+
+  useEffect(() => {
+    logger.info("Smoke page mounted", { locale: lang ?? "unknown" });
+  }, [logger, lang]);
+
+  return (
+    <main style={{ padding: "2rem" }}>
+      <h1>{t("SMOKE.HEADING")}</h1>
+      <dl>
+        <dt>Locale</dt>
+        <dd>{lang}</dd>
+        <dt>i18n test (BOARD.DEPARTURE)</dt>
+        <dd>{t("BOARD.DEPARTURE")}</dd>
+      </dl>
+      <p>
+        If you can see translated text above, the i18n provider is working.
+      </p>
+    </main>
+  );
+}