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/search-service/src/lib/searxng.ts

@@ -0,0 +1,48 @@
+import { getSearxngURL } from './config/serverRegistry';
+
+interface SearxngSearchOptions {
+  categories?: string[];
+  engines?: string[];
+  language?: string;
+  pageno?: number;
+}
+
+interface SearxngSearchResult {
+  title: string;
+  url: string;
+  img_src?: string;
+  thumbnail_src?: string;
+  thumbnail?: string;
+  content?: string;
+  author?: string;
+  iframe_src?: string;
+}
+
+export const searchSearxng = async (
+  query: string,
+  opts?: SearxngSearchOptions,
+) => {
+  const searxngURL = getSearxngURL();
+
+  const url = new URL(`${searxngURL}/search?format=json`);
+  url.searchParams.append('q', query);
+
+  if (opts) {
+    Object.keys(opts).forEach((key) => {
+      const value = opts[key as keyof SearxngSearchOptions];
+      if (Array.isArray(value)) {
+        url.searchParams.append(key, value.join(','));
+        return;
+      }
+      url.searchParams.append(key, value as string);
+    });
+  }
+
+  const res = await fetch(url);
+  const data = await res.json();
+
+  const results: SearxngSearchResult[] = data.results;
+  const suggestions: string[] = data.suggestions;
+
+  return { results, suggestions };
+};