Supprime nginx : Express sert le frontend, ports peu utilisés

- Un seul conteneur applicatif : Express sert l'API, le frontend React
  compilé (fallback SPA, cache immutable sur /assets) et les images
  /uploads (nosniff + CSP default-src 'none')
- En-têtes de sécurité (CSP stricte, X-Frame-Options DENY, etc.) portés
  de nginx vers helmet, compression gzip ajoutée
- Application exposée sur le port 8321 (APP_PORT), PostgreSQL sur
  127.0.0.1:56432 (DB_PORT, loopback uniquement pour l'admin locale)
- TRUST_PROXY pilote la confiance aux en-têtes X-Forwarded-* (désactivé
  par défaut hors reverse-proxy)
- Dockerfile multi-étages unique à la racine (build React → deps → image
  finale non-root, fs en lecture seule)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Fkg15RCxNgUys4ru73He2o

Dockerfile

@@ -0,0 +1,30 @@
+# Stage 1 — build the React frontend
+FROM node:22-alpine AS webbuild
+WORKDIR /build
+COPY web/package.json web/package-lock.json* ./
+RUN npm ci 2>/dev/null || npm install
+COPY web/index.html web/vite.config.js ./
+COPY web/public ./public
+COPY web/src ./src
+RUN npm run build
+
+# Stage 2 — install API production dependencies
+FROM node:22-alpine AS deps
+WORKDIR /app
+COPY server/package.json server/package-lock.json* ./
+RUN npm ci --omit=dev 2>/dev/null || npm install --omit=dev
+
+# Stage 3 — final image: Express serves the API, the frontend and the uploads
+FROM node:22-alpine
+ENV NODE_ENV=production
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY server/package.json ./
+COPY server/src ./src
+COPY --from=webbuild /build/dist ./public
+# Upload dir owned by the app user; a named volume mounted here inherits
+# this ownership on first use
+RUN mkdir -p /data/uploads && chown node:node /data/uploads
+USER node
+EXPOSE 3000
+CMD ["node", "src/index.js"]