Use 'npm ci --ignore-scripts' + explicit 'npx prisma generate' instead
of 'npm install' (which triggered postinstall and ran with NODE_ENV=production
from a sourced .env, skipping devDependencies like autoprefixer).
Migrations are run explicitly after build, matching the Dockerfile's
container-entrypoint.sh.
Spliit imports deepmerge in src/i18n/request.ts but does not declare it
in package.json; Next.js 16 Turbopack rejects phantom dependencies, so
the build fails with 'Module not found: deepmerge'.