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>

README.md

@@ -121,10 +121,12 @@ If you prefer to build from source or need more control:
 4. Build and run using Docker:
 
    ```bash
-   docker build -t gooseek .
+   docker build -f docker/Dockerfile -t gooseek .
    docker run -d -p 3000:3000 -v gooseek-data:/home/gooseek/data --name gooseek gooseek
    ```
 
+   Or use compose: `docker compose -f docker/docker-compose.yaml up -d`
+
 5. Access GooSeek at http://localhost:3000 and configure your settings in the setup screen.
 
 **Note**: After the containers are built, you can start GooSeek directly from Docker without having to open a terminal.