build(docker): build frontend and server inside container; remove host build deps

docker/Dockerfile.dev

@@ -1,19 +1,42 @@
-FROM node:20-bullseye-slim
+######
+# Multi-stage dev image that builds frontend and server inside container
+######
+
+# ---------- Frontend builder ----------
+FROM node:20-bullseye-slim AS frontend-builder
+ENV npm_config_registry=https://registry.npmmirror.com
+WORKDIR /app
+COPY package.json ./
+COPY pnpm-lock.yaml ./
+RUN npm install --no-audit --no-fund
+COPY . .
+RUN npm run build
+
+# ---------- Server builder ----------
+FROM node:20-bullseye-slim AS server-builder
 ENV npm_config_registry=https://registry.npmmirror.com
 ENV npm_config_build_from_source=true
-
-# Build prerequisites for native modules (better-sqlite3)
 RUN apt-get update \
     && apt-get install -y --no-install-recommends python3 make g++ \
     && rm -rf /var/lib/apt/lists/*
+WORKDIR /app/server
+COPY server/package.json ./package.json
+RUN npm install --no-audit --no-fund --build-from-source
+COPY server/tsconfig.json ./tsconfig.json
+COPY server/src ./src
+RUN npm run build
 
+# ---------- Runtime ----------
+FROM node:20-bullseye-slim
+ENV npm_config_registry=https://registry.npmmirror.com
 WORKDIR /app
+ENV PORT=3004
+ENV DB_PATH=/data/purchase.db
 
-# Use host-built frontend; only run server here
-COPY server/package.json server/tsconfig.json ./server/
-COPY server/src ./server/src
-
-RUN cd server && npm install --build-from-source && npm run build
+COPY --from=server-builder /app/server/dist ./server/dist
+COPY --from=server-builder /app/server/node_modules ./server/node_modules
+COPY server/package.json ./server/package.json
+COPY --from=frontend-builder /app/dist ./frontend
 
 EXPOSE 3004
 CMD ["node", "server/dist/index.js"]