Add configuration files and update project documentation

- Introduced .editorconfig for consistent coding styles across the project.
- Added .golangci.yml for Go linting configuration.
- Updated AGENTS.md to clarify project structure and components.
- Enhanced CONTRIBUTING.md with Makefile usage for common tasks.
- Updated Dockerfiles to use Go 1.24 and improved build instructions.
- Refined README.md and deployment documentation for clarity.
- Added testing documentation in testing.md for backend and frontend tests.
- Introduced Makefile for streamlined development commands and tasks.

docs/development.md

@@ -1,25 +1,25 @@
-# Разработка
+# Development
 
-## Локальный запуск
+## Local setup
 
-### Бэкенд (Go)
+### Backend (Go)
 
-Из корня репозитория:
+From the repository root:
 
 ```bash
 go build -o hnh-map ./cmd/hnh-map
 ./hnh-map -grids=./grids -port=8080
 ```
 
-Или без сборки:
+Or without building:
 
 ```bash
 go run ./cmd/hnh-map -grids=./grids -port=8080
 ```
 
-Сервер будет отдавать статику из каталога `frontend/` (нужно предварительно собрать фронт, см. ниже).
+The server serves static files from the `frontend/` directory (you need to build the frontend first, see below).
 
-### Фронтенд (Nuxt)
+### Frontend (Nuxt)
 
 ```bash
 cd frontend-nuxt
@@ -27,27 +27,72 @@ npm install
 npm run dev
 ```
 
-В dev-режиме приложение доступно по корню (например `http://localhost:3000/`). Бэкенд должен быть доступен; при необходимости настройте прокси в `nuxt.config.ts` (например на `http://localhost:8080`).
+In dev mode the app is available at root (e.g. `http://localhost:3000/`). The backend must be reachable; configure the proxy in `nuxt.config.ts` if needed (e.g. to `http://localhost:8080`).
 
-### Docker Compose (разработка)
+### Docker Compose (development)
 
 ```bash
 docker compose -f docker-compose.dev.yml up
 ```
 
-Dev-композ поднимает два сервиса:
+Or using the Makefile:
 
-- `backend` — Go API на порту `3080` (без сборки/раздачи фронтенд-статики в dev-режиме).
-- `frontend` — Nuxt dev-сервер на порту `3000` с live-reload; запросы к `/map/api`, `/map/updates`, `/map/grids` проксируются на бэкенд.
+```bash
+make dev
+```
 
-Используйте [http://localhost:3000/](http://localhost:3000/) как основной URL для разработки интерфейса.
-Порт `3080` предназначен для API и backend-эндпоинтов; корень `/` может возвращать `404` в dev-режиме — это ожидаемо.
+The dev Compose setup starts two services:
 
-### Сборка образа и prod-композ
+- `backend` — Go API on port `3080` (no frontend static serving in dev mode).
+- `frontend` — Nuxt dev server on port `3000` with live-reload; requests to `/map/api`, `/map/updates`, `/map/grids` are proxied to the backend.
+
+Use [http://localhost:3000/](http://localhost:3000/) as the primary URL for UI development.
+Port `3080` is for API and backend endpoints; the root `/` may return `404` in dev mode — this is expected.
+
+### Building the image and production Compose
 
 ```bash
 docker build -t hnh-map .
 docker compose -f docker-compose.prod.yml up -d
 ```
 
-В prod фронт собран в образ и отдаётся бэкендом из каталога `frontend/`; порт 8080.
+Or using the Makefile:
+
+```bash
+make build
+```
+
+In production the frontend is built into the image and served by the backend from the `frontend/` directory; port 8080.
+
+## Makefile targets
+
+| Target | Description |
+|--------|-------------|
+| `make dev` | Start Docker Compose development environment |
+| `make build` | Build production Docker image |
+| `make test` | Run Go tests (`go test ./...`) |
+| `make lint` | Run Go and frontend linters |
+| `make fmt` | Format all code (Go + frontend) |
+| `make generate-frontend` | Build frontend static output into `frontend/` |
+| `make clean` | Remove build artifacts |
+
+## Running tests
+
+```bash
+make test
+```
+
+Or directly:
+
+```bash
+go test ./...
+```
+
+For frontend tests (if configured):
+
+```bash
+cd frontend-nuxt
+npm test
+```
+
+See [docs/testing.md](testing.md) for details on the test suite.