feat: монорепо миграция, Discover/SearxNG улучшения

- Миграция на монорепозиторий (apps/frontend, apps/chat-service, etc.)
- Discover: проверка SearxNG, понятное empty state при ненастроенном поиске
- searxng.ts: валидация URL, проверка JSON-ответа, авто-добавление http://
- docker/searxng-config: настройки для JSON API SearxNG

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/frontend/src/components/EmptyChat.tsx

@@ -0,0 +1,75 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { Settings } from 'lucide-react';
+import EmptyChatMessageInput from './EmptyChatMessageInput';
+import { File } from './ChatWindow';
+import Link from 'next/link';
+import WeatherWidget from './WeatherWidget';
+import NewsArticleWidget from './NewsArticleWidget';
+import SettingsButtonMobile from '@/components/Settings/SettingsButtonMobile';
+import {
+  getShowNewsWidget,
+  getShowWeatherWidget,
+} from '@/lib/config/clientRegistry';
+
+const EmptyChat = () => {
+  const [showWeather, setShowWeather] = useState(() =>
+    typeof window !== 'undefined' ? getShowWeatherWidget() : true,
+  );
+  const [showNews, setShowNews] = useState(() =>
+    typeof window !== 'undefined' ? getShowNewsWidget() : true,
+  );
+
+  useEffect(() => {
+    const updateWidgetVisibility = () => {
+      setShowWeather(getShowWeatherWidget());
+      setShowNews(getShowNewsWidget());
+    };
+
+    updateWidgetVisibility();
+
+    window.addEventListener('client-config-changed', updateWidgetVisibility);
+    window.addEventListener('storage', updateWidgetVisibility);
+
+    return () => {
+      window.removeEventListener(
+        'client-config-changed',
+        updateWidgetVisibility,
+      );
+      window.removeEventListener('storage', updateWidgetVisibility);
+    };
+  }, []);
+
+  return (
+    <div className="relative">
+      <div className="absolute w-full flex flex-row items-center justify-end mr-5 mt-5">
+        <SettingsButtonMobile />
+      </div>
+      <div className="flex flex-col items-center justify-center min-h-screen max-w-screen-sm mx-auto p-2 space-y-4">
+        <div className="flex flex-col items-center justify-center w-full space-y-8">
+          <h2 className="text-black/70 dark:text-white/70 text-3xl font-medium -mt-8">
+            Research begins here.
+          </h2>
+          <EmptyChatMessageInput />
+        </div>
+        {(showWeather || showNews) && (
+          <div className="flex flex-col w-full gap-4 mt-2 sm:flex-row sm:justify-center">
+            {showWeather && (
+              <div className="flex-1 w-full">
+                <WeatherWidget />
+              </div>
+            )}
+            {showNews && (
+              <div className="flex-1 w-full">
+                <NewsArticleWidget />
+              </div>
+            )}
+          </div>
+        )}
+      </div>
+    </div>
+  );
+};
+
+export default EmptyChat;