Plain-JS Next config so the image boots without devDependencies

next start stops to install TypeScript when the config is a .ts file, which in
the container meant a yarn install into node_modules on every boot — slow
enough that the health check failed before the server answered.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Dockerfile

@@ -52,7 +52,7 @@ RUN mkdir -p /data && chown nextjs:nodejs /data
 
 COPY --from=proddeps --chown=nextjs:nodejs /app/node_modules ./node_modules
 COPY --from=builder  --chown=nextjs:nodejs /app/.next ./.next
-COPY --chown=nextjs:nodejs package.json next.config.ts ./
+COPY --chown=nextjs:nodejs package.json next.config.mjs ./
 COPY --chown=nextjs:nodejs public ./public
 # /api/autobuyer/status reads the version out of this manifest and the extension
 # reloads itself to match, so the folder has to travel with the server.
@@ -61,7 +61,7 @@ COPY --chown=nextjs:nodejs extension ./extension
 USER nextjs
 EXPOSE 3000
 
-HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
+HEALTHCHECK --interval=15s --timeout=10s --start-period=20s --retries=5 \
     CMD node -e "fetch('http://127.0.0.1:3000/api/autobuyer/status').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))"
 
 CMD ["npm", "start"]