build: switch frontend docker image to node20

frontend/Dockerfile

@@ -1,19 +1,21 @@
-FROM node:22-alpine AS deps
+FROM node:20-bookworm-slim AS deps
 WORKDIR /app
 COPY package.json package-lock.json ./
 RUN npm ci
 
-FROM node:22-alpine AS builder
+FROM node:20-bookworm-slim AS builder
 WORKDIR /app
 COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 ARG BACKEND_BASE_URL=http://backend:8000
 ENV BACKEND_BASE_URL=${BACKEND_BASE_URL}
+ENV NEXT_TELEMETRY_DISABLED=1
 RUN npm run build -- --webpack
 
-FROM node:22-alpine AS runner
+FROM node:20-bookworm-slim AS runner
 WORKDIR /app
 ENV NODE_ENV=production
+ENV NEXT_TELEMETRY_DISABLED=1
 
 COPY --from=builder /app/package.json ./package.json
 COPY --from=builder /app/package-lock.json ./package-lock.json