fix: frontend and backend now get variables at build time not runtime

frontend/Dockerfile

@@ -24,6 +24,9 @@ WORKDIR /app
 COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 
+ARG NEXT_PUBLIC_BACKEND_URL
+ENV NEXT_PUBLIC_BACKEND_URL=$NEXT_PUBLIC_BACKEND_URL
+
 # Next.js collects completely anonymous telemetry data about general usage.
 # Learn more here: https://nextjs.org/telemetry
 # Uncomment the following line in case you want to disable telemetry during the build.

frontend/next.config.ts

@@ -1,7 +1,4 @@
 import type { NextConfig } from "next";
-import dotenv from "dotenv";
-
-dotenv.config({ path: "../.env" });
 
 const nextConfig: NextConfig = {
   output: "standalone",