feat: minimal prod compose with watchtower auto-updates

frontend/Dockerfile

@@ -0,0 +1,13 @@
+# Production image for the React UI (build + Vite preview; internal use).
+FROM node:22-slim
+
+WORKDIR /srv/frontend
+COPY package.json package-lock.json ./
+RUN npm ci
+COPY . ./
+RUN npm run build
+
+ENV VITE_API_PROXY_TARGET=http://app:8000
+EXPOSE 3000
+
+CMD ["npm", "run", "preview", "--", "--host", "0.0.0.0", "--port", "3000"]

frontend/vite.config.ts

@@ -12,4 +12,14 @@ export default defineConfig({
       },
     },
   },
+  preview: {
+    port: 3000,
+    proxy: {
+      "/api": {
+        // Overridable at container start (prod compose: http://app:8000).
+        target: process.env.VITE_API_PROXY_TARGET ?? "http://localhost:8000",
+        changeOrigin: true,
+      },
+    },
+  },
 });