feat(sp23): frontend Dockerfile + nginx.conf (SPA + reverse proxy)

frontend/Dockerfile

@@ -0,0 +1,33 @@
+# syntax=docker/dockerfile:1.7
+#
+# Cyclone frontend — React SPA built with node:20-alpine and served by
+# nginx:1.27-alpine. nginx reverse-proxies /api/* to the backend service
+# over the compose-managed bridge network.
+
+# ---------- builder ----------
+FROM node:20-alpine AS builder
+
+WORKDIR /build
+
+# Install deps first so this layer caches across source edits.
+COPY package.json package-lock.json* ./
+RUN npm ci
+
+# Build the production bundle into dist/.
+COPY . .
+RUN npm run build
+
+# ---------- runtime ----------
+FROM nginx:1.27-alpine
+
+# Replace the default nginx site with ours (SPA + reverse proxy).
+RUN rm -f /etc/nginx/conf.d/default.conf
+
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=builder /build/dist /usr/share/nginx/html
+
+# wget is on busybox; nginx:alpine doesn't ship curl.
+HEALTHCHECK --interval=30s --timeout=5s --retries=3 \
+    CMD wget -qO- http://localhost:8080/ >/dev/null || exit 1
+
+EXPOSE 8080