Add graceful API error state with retry on search pages

When the API fetch fails (backend unavailable), show a styled white
error card with a Russian-language message and retry button instead
of barely-visible text on a dark background.

src/features/online-board/components/OnlineBoardSearchPage.scss

@@ -19,11 +19,41 @@
     }
   }
 
-  &__error {
+  &__error-card {
+    background: colors.$white;
+    border-radius: vars.$border-radius;
     padding: vars.$space-xl;
+    text-align: center;
+  }
+
+  &__error-title {
+    margin: 0 0 vars.$space-m;
+    font-size: 18px;
     color: colors.$red;
   }
 
+  &__error-message {
+    margin: 0 0 vars.$space-xl;
+    color: #666;
+    font-size: 14px;
+  }
+
+  &__retry-btn {
+    display: inline-block;
+    padding: vars.$space-s2 vars.$space-xl;
+    background-color: colors.$blue;
+    color: colors.$white;
+    border: none;
+    border-radius: vars.$border-radius;
+    cursor: pointer;
+    font-size: 14px;
+    font-weight: 500;
+
+    &:hover {
+      opacity: 0.9;
+    }
+  }
+
   &__actions {
     display: none;
   }

src/features/online-board/components/OnlineBoardSearchPage.tsx

@@ -15,7 +15,11 @@
 import type { FC } from "react";
 import { useCallback } from "react";
 import { useNavigate, useParams } from "@modern-js/runtime/router";
+import { useTranslation } from "@/i18n/provider.js";
 import { FlightList } from "@/ui/flights/FlightList.js";
+import { PageLayout } from "@/ui/layout/PageLayout.js";
+import { PageTabs } from "@/ui/layout/PageTabs.js";
+import { OnlineBoardFilter } from "./OnlineBoardFilter.js";
 import "./OnlineBoardSearchPage.scss";
 import { JsonLdRenderer } from "@/shared/seo/json-ld.js";
 import { useOnlineBoard } from "../hooks/useOnlineBoard.js";
@@ -133,6 +137,7 @@ export const OnlineBoardSearchPage: FC<OnlineBoardSearchPageProps> = ({
   params,
 }) => {
   const navigate = useNavigate();
+  const { t } = useTranslation();
   const routeParams = useParams<{ lang: string }>();
   const lang = routeParams.lang ?? "ru";
 
@@ -196,62 +201,85 @@ export const OnlineBoardSearchPage: FC<OnlineBoardSearchPageProps> = ({
   return (
     <div className="online-board-search" data-testid="online-board-search">
       {jsonLd && <JsonLdRenderer data={jsonLd} />}
-      {/* Connection status indicator */}
-      <div className="online-board-search__status" data-testid="connection-status">
-        {connectionStatus === "live" && (
-          <span className="connection-badge connection-badge--live">Live</span>
-        )}
-        {connectionStatus === "reconnecting" && (
-          <span className="connection-badge connection-badge--reconnecting">Reconnecting...</span>
-        )}
-        {connectionStatus === "offline" && (
-          <span className="connection-badge connection-badge--offline">Offline</span>
-        )}
-      </div>
-
-      {/* Calendar strip (simple date list for now) */}
-      {calendarDays.length > 0 && (
-        <div className="online-board-search__calendar" data-testid="calendar-strip">
-          {calendarDays.map((day) => (
-            <button
-              key={day}
-              type="button"
-              className={`calendar-day${day === params.date ? " calendar-day--active" : ""}`}
-              onClick={() => handleDateChange(day)}
-            >
-              {day}
-            </button>
-          ))}
+      <PageLayout
+        headerLeft={<PageTabs viewType="onlineboard" />}
+        title={
+          <h1 className="text--white page-title">
+            {t("BOARD.TITLE")}
+          </h1>
+        }
+        contentLeft={<OnlineBoardFilter />}
+        stickyContent={
+          calendarDays.length > 0 ? (
+            <div className="online-board-search__calendar" data-testid="calendar-strip">
+              {calendarDays.map((day) => (
+                <button
+                  key={day}
+                  type="button"
+                  className={`calendar-day${day === params.date ? " calendar-day--active" : ""}`}
+                  onClick={() => handleDateChange(day)}
+                >
+                  {day}
+                </button>
+              ))}
+            </div>
+          ) : undefined
+        }
+      >
+        {/* Connection status indicator */}
+        <div className="online-board-search__status" data-testid="connection-status">
+          {connectionStatus === "live" && (
+            <span className="connection-badge connection-badge--live">Live</span>
+          )}
+          {connectionStatus === "reconnecting" && (
+            <span className="connection-badge connection-badge--reconnecting">Reconnecting...</span>
+          )}
+          {connectionStatus === "offline" && (
+            <span className="connection-badge connection-badge--offline">Offline</span>
+          )}
         </div>
-      )}
 
-      {/* Error state */}
-      {error && (
-        <div className="online-board-search__error" data-testid="search-error">
-          <p>Failed to load flights. Please try again.</p>
-          <button type="button" onClick={refresh}>Retry</button>
-        </div>
-      )}
+        {/* Error state */}
+        {error && (
+          <section className="frame" data-testid="search-error">
+            <div className="online-board-search__error-card">
+              <h3 className="online-board-search__error-title">
+                Не удалось загрузить данные
+              </h3>
+              <p className="online-board-search__error-message">
+                API сервер недоступен. Проверьте подключение и попробуйте снова.
+              </p>
+              <button
+                type="button"
+                className="online-board-search__retry-btn"
+                onClick={refresh}
+              >
+                Повторить
+              </button>
+            </div>
+          </section>
+        )}
 
-      {/* Flight list */}
-      <FlightList flights={displayFlights} loading={loading} />
+        {/* Flight list */}
+        {!error && <FlightList flights={displayFlights} loading={loading} />}
 
-      {/* Flight click overlay — we make the list clickable */}
-      {!loading && displayFlights.length > 0 && (
-        <div className="online-board-search__actions" data-testid="flight-actions">
-          {displayFlights.map((flight) => (
-            <button
-              key={flight.id}
-              type="button"
-              className="flight-detail-link"
-              data-testid={`flight-link-${flight.id}`}
-              onClick={() => handleFlightClick(flight)}
-            >
-              View details for {flight.flightId.carrier} {flight.flightId.flightNumber}
-            </button>
-          ))}
-        </div>
-      )}
+        {/* Flight click overlay — we make the list clickable */}
+        {!loading && displayFlights.length > 0 && (
+          <div className="online-board-search__actions" data-testid="flight-actions">
+            {displayFlights.map((flight) => (
+              <button
+                key={flight.id}
+                type="button"
+                className="flight-detail-link"
+                data-testid={`flight-link-${flight.id}`}
+                onClick={() => handleFlightClick(flight)}
+              >
+                View details for {flight.flightId.carrier} {flight.flightId.flightNumber}
+              </button>
+            ))}
+          </div>
+        )}
+      </PageLayout>
     </div>
   );
 };