chore: initial project setup with backend, frontend, and infrastructure

Add complete NexaPantry application structure including:
- Docker Compose configuration with PostgreSQL, Redis, FastAPI backend, worker, frontend and Caddy
- Environment configuration template with database, auth, and service settings
- GitHub Actions CI workflow for backend/frontend linting, testing, auditing and Docker builds
- AGPL-3.0 license and comprehensive README with setup, development, and security documentation
- Backend

frontend/Dockerfile

@@ -0,0 +1,12 @@
+FROM node:22-alpine AS build
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM nginxinc/nginx-unprivileged:1.27-alpine AS runtime
+COPY nginx.conf /etc/nginx/nginx.conf
+COPY --from=build /app/dist /usr/share/nginx/html
+EXPOSE 8080
+HEALTHCHECK CMD wget -qO- http://127.0.0.1:8080/ || exit 1