chore(devops): docker-compose dev + prod, Dockerfiles, nginx, Makefile

- backend/Dockerfile: Python 3.12 slim, non-root user, WeasyPrint system deps
- backend/Dockerfile.dev: dev variant with hot-reload support
- frontend/Dockerfile: Node 20 alpine build + nginx:alpine serve
- frontend/nginx.conf: SPA routing + /api proxy to backend:8000
- docker-compose.yml: production with healthcheck
- docker-compose.dev.yml: dev with volume mounts and hot-reload
- Makefile: dev, build, up, down, logs, migrate, test, shell, prod targets
- .dockerignore for backend and frontend

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

docker-compose.dev.yml

@@ -0,0 +1,26 @@
+services:
+  backend:
+    build:
+      context: ./backend
+      dockerfile: Dockerfile.dev
+    ports:
+      - "8000:8000"
+    volumes:
+      - ./backend:/app
+      - ./backend/data:/app/data
+    environment:
+      - DATABASE_URL=sqlite+aiosqlite:///./data/roaauto.db
+      - SECRET_KEY=dev-secret-key-change-in-prod
+      - CORS_ORIGINS=http://localhost:5173
+    command: uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload
+
+  frontend:
+    image: node:20-alpine
+    ports:
+      - "5173:5173"
+    volumes:
+      - ./frontend:/app
+    working_dir: /app
+    environment:
+      - VITE_API_URL=http://localhost:8000/api
+    command: sh -c "npm install && npm run dev -- --host"