fix: use backend:8000 for container network in wizard default

Dockerfile

@@ -3,13 +3,6 @@ FROM node:20-alpine AS build
 WORKDIR /app
 COPY package.json package-lock.json* ./
 RUN npm install
-
-# Set build args and env vars BEFORE copying source code
-ARG VITE_WIZARD_PORT=18080
-ARG VITE_API_BASE
-ENV VITE_WIZARD_PORT=$VITE_WIZARD_PORT
-ENV VITE_API_BASE=$VITE_API_BASE
-
 COPY . .
 RUN npm run build