deploy: route frontend and core through one origin

docker/frontend.Dockerfile

@@ -1,21 +1,17 @@
 # syntax=docker/dockerfile:1.7
 # thothii-frontend: build Vite (React) + nginx-unprivileged (porta 8080).
-# Build args:
-#   VITE_BASE         prefisso asset ("/" standalone, "/datamart-builder/assets/" embedded)
-#   VITE_BACKEND_URL  base API ("http://localhost:8787" standalone, "/datamart-builder/api" embedded)
 FROM node:22-bookworm AS build
 WORKDIR /src
 COPY frontend/package*.json ./
 RUN npm ci
 COPY frontend/ ./
-ARG VITE_BASE=/
-ARG VITE_BACKEND_URL=http://localhost:8787
-ENV VITE_BASE=$VITE_BASE VITE_BACKEND_URL=$VITE_BACKEND_URL
+ENV VITE_BASE=/ VITE_BACKEND_URL=/api
 RUN npm run build
-# typecheck opzionale (non bloccante nella build dell'immagine)
-RUN npx tsc -b 2>/dev/null || true
 
 FROM nginxinc/nginx-unprivileged:1.27-alpine AS runtime
 COPY --from=build /src/dist /usr/share/nginx/html
-COPY docker/nginx.conf /etc/nginx/conf.d/default.conf
+COPY docker/nginx.conf.template /etc/nginx/templates/default.conf.template
+COPY --chmod=755 docker/frontend-entrypoint.sh /usr/local/bin/frontend-entrypoint
+ENTRYPOINT ["/usr/local/bin/frontend-entrypoint"]
+CMD ["nginx", "-g", "daemon off;"]
 EXPOSE 8080