Fix reproducible frontend Docker deployment

Dockerfile

@@ -12,24 +12,9 @@ COPY . .
 ENV NODE_ENV=production
 RUN npm run build || exit 1
 
-# Production stage
-FROM node:22-alpine AS runtime
-WORKDIR /app
-
-# Copy built assets and dependencies
-COPY --from=builder /app/build ./build
-COPY --from=builder /app/node_modules ./node_modules
-COPY package.json .
-
-# Non-root user
-RUN addgroup -S nsct && adduser -S nsct -G nsct
-USER nsct
-
-# Health check
-HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 CMD wget -qO- http://localhost:3000/health || exit 1
+# Production stage: serve the static SvelteKit output.
+FROM caddy:2.8-alpine AS runtime
+COPY Caddyfile.web /etc/caddy/Caddyfile
+COPY --from=builder /app/build /usr/share/caddy
 
 EXPOSE 3000
-ENV HOST=0.0.0.0
-ENV PORT=3000
-
-CMD ["node", "build"]