Add production Docker setup

- Dockerfile: multi-stage build (deps → builder → standalone runner)
- docker-compose.prod.yml: app on port 3010 + PostgreSQL 16
- entrypoint.sh: runs prisma migrate deploy then starts node server
- next.config.ts: standalone output for minimal Docker image
- .dockerignore: exclude dev files from build context

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.prod.yml

@@ -0,0 +1,36 @@
+services:
+  app:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    restart: unless-stopped
+    ports:
+      - "3010:3000"
+    environment:
+      DATABASE_URL: "postgresql://lms_user:${DB_PASSWORD}@db:5432/lms_db"
+      BETTER_AUTH_SECRET: "${BETTER_AUTH_SECRET}"
+      BETTER_AUTH_URL: "https://school.second-brain.ru"
+      NEXT_PUBLIC_APP_URL: "https://school.second-brain.ru"
+      RESEND_API_KEY: "${RESEND_API_KEY}"
+      EMAIL_FROM: "${EMAIL_FROM}"
+    depends_on:
+      db:
+        condition: service_healthy
+
+  db:
+    image: postgres:16-alpine
+    restart: unless-stopped
+    environment:
+      POSTGRES_USER: lms_user
+      POSTGRES_PASSWORD: "${DB_PASSWORD}"
+      POSTGRES_DB: lms_db
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U lms_user -d lms_db"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
+volumes:
+  postgres_data: