conditional build

Dockerfile

@@ -3,6 +3,9 @@
 # =======================
 FROM node:22-slim AS frontend-builder
 
+# Accept SPACE_HOST as build argument
+ARG SPACE_HOST
+
 # Install pnpm globally
 RUN corepack enable && corepack prepare pnpm@latest --activate
 
@@ -18,9 +21,15 @@ RUN pnpm install --frozen-lockfile
 # Copy the rest of the frontend source
 COPY frontend/ ./
 
-# Build frontend
+# Build frontend with SPACE_HOST as VITE_BACKEND_URL if provided
 ENV VITE_APP_ENV=production
-RUN pnpm build
+RUN if [ -n "$SPACE_HOST" ]; then \
+        echo "Building with SPACE_HOST: $SPACE_HOST"; \
+        VITE_BACKEND_URL="$SPACE_HOST" pnpm build; \
+    else \
+        echo "Building without SPACE_HOST"; \
+        pnpm build; \
+    fi
 
 
 # =======================