Add initial project structure with backend and frontend setup

- Created backend structure with Go, including main application logic and API endpoints.
- Added Docker support for both development and production environments.
- Introduced frontend using Nuxt 3 with Tailwind CSS for styling.
- Included configuration files for Docker and environment variables.
- Established basic documentation for contributing, development, and deployment processes.
- Set up .gitignore and .dockerignore files to manage ignored files in the repository.

docker-compose.dev.yml

@@ -0,0 +1,30 @@
+# Development: backend (Go) on 8080, frontend (Nuxt dev) on 3000 with proxy to backend.
+# Open http://localhost:3000/map/ — /map/api, /map/updates, /map/grids are proxied to backend.
+
+services:
+  backend:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    ports:
+      - "3080:3080"
+    volumes:
+      - ./grids:/map
+    environment:
+      - HNHMAP_PORT=3080
+      - HNHMAP_BOOTSTRAP_PASSWORD=admin
+
+  frontend:
+    image: node:20-alpine
+    working_dir: /app
+    command: sh -c "npm ci && npm run dev"
+    ports:
+      - "3000:3000"
+    volumes:
+      - ./frontend-nuxt:/app
+      # Prevent overwriting node_modules from host
+      - /app/node_modules
+    environment:
+      - NUXT_PUBLIC_API_BASE=/map/api
+    depends_on:
+      - backend