feat(03-04): Dockerfile SSR multi-stage + docker-compose Traefik port 3000

- Rewrite Dockerfile: node:22-alpine build + runtime, copy .output/, node server
- Add .dockerignore excluding node_modules, .nuxt, .output, src, .git, .planning
- Update docker-compose loadbalancer port from 80 to 3000
- Add SMTP and GA4 environment variables to docker-compose

Dockerfile

@@ -1,32 +1,17 @@
-# Stage 1: Build the Vue.js application
-FROM node:22-alpine AS build-stage
-
+# Stage 1: Build
+FROM node:22-alpine AS builder
 WORKDIR /app
-
-# Copy package.json and package-lock.json (or yarn.lock)
 COPY package*.json ./
-
-# Install dependencies
-RUN npm install
-
-# Copy the rest of your application's source code
+RUN npm ci
 COPY . .
-
-# Build the application
-# The command is taken from your "scripts" in package.json
 RUN npm run build
 
-# Stage 2: Serve the application with a lightweight web server
-FROM nginx:stable-alpine AS production-stage
-
-# Copy the built files from the build stage
-COPY --from=build-stage /app/dist /usr/share/nginx/html
-
-# Copy the nginx configuration file
-COPY nginx.conf /etc/nginx/conf.d/default.conf
-
-# Expose port 80 to the outside world
-EXPOSE 80
-
-# Command to run nginx in the foreground
-CMD ["nginx", "-g", "daemon off;"]
+# Stage 2: Runtime
+FROM node:22-alpine AS runner
+ENV NODE_ENV=production
+ENV HOST=0.0.0.0
+ENV PORT=3000
+WORKDIR /app
+COPY --from=builder /app/.output /app/.output
+EXPOSE 3000
+CMD ["node", "/app/.output/server/index.mjs"]