feat: unify on single repo-root compose file for dev and prod

frontend/Dockerfile

@@ -1,13 +1,13 @@
-# Production image for the React UI (build + Vite preview; internal use).
+# Frontend image for dev and prod (single image).
+# Dev specifics arrive via devcontainer.json / compose env — never via this
+# file. DevDeps are included: `npm run dev` must work with zero steps.
 FROM node:22-slim
 
-WORKDIR /srv/frontend
-COPY package.json package-lock.json ./
-RUN npm ci
+WORKDIR /srv/kirche-einfach/frontend
+COPY package.json package-lock.json entrypoint.sh ./
+RUN npm ci && chmod +x entrypoint.sh
 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"]
+ENTRYPOINT ["./entrypoint.sh"]

frontend/entrypoint.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+# Frontend entrypoint (dev + prod).
+# FRONTEND_MODE=dev (compose default) runs the HMR dev server.
+# FRONTEND_MODE=preview (prod .env) builds once and serves the bundle.
+set -e
+
+cd /srv/kirche-einfach/frontend
+
+if [ "${FRONTEND_MODE:-dev}" = "dev" ]; then
+  exec npm run dev -- --host 0.0.0.0 --port 3000
+else
+  npm run build
+  exec npm run preview -- --host 0.0.0.0 --port 3000
+fi

frontend/vite.config.ts

@@ -1,13 +1,15 @@
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
 
+// Both dev server and preview proxy /api to the backend service.
+// `api` is the compose service name, identical in dev and prod.
 export default defineConfig({
   plugins: [react()],
   server: {
     port: 3000,
     proxy: {
       "/api": {
-        target: "http://localhost:8000",
+        target: "http://api:8000",
         changeOrigin: true,
       },
     },
@@ -16,8 +18,7 @@ export default defineConfig({
     port: 3000,
     proxy: {
       "/api": {
-        // Overridable at container start (prod compose: http://app:8000).
-        target: process.env.VITE_API_PROXY_TARGET ?? "http://localhost:8000",
+        target: "http://api:8000",
         changeOrigin: true,
       },
     },