feat(docker): add Docker setup, environment examples, and architecture docs

Dockerfile

@@ -0,0 +1,28 @@
+FROM node:20-alpine AS builder
+WORKDIR /app
+
+COPY package*.json ./
+RUN if [ -f package-lock.json ]; then npm ci --no-audit --no-fund; else npm install --no-audit --no-fund; fi
+
+COPY . ./
+RUN npm run build
+
+FROM node:20-alpine AS runner
+WORKDIR /app
+
+LABEL org.opencontainers.image.title="9router"
+
+ENV NODE_ENV=production
+ENV PORT=20128
+ENV HOSTNAME=0.0.0.0
+
+# Runtime writable location for localDb when DATA_DIR is configured to /app/data
+RUN mkdir -p /app/data
+
+COPY --from=builder /app/public ./public
+COPY --from=builder /app/.next/static ./.next/static
+COPY --from=builder /app/.next/standalone ./
+
+EXPOSE 20128
+
+CMD ["node", "server.js"]