Next.js locale routing — standalone site

Locale-prefixed routing for one Next.js App Router app, no shared package. Every page lives under /<locale>/…; a proxy (middleware) sends unprefixed requests to the right locale. Drop-in copy-paste files are in templates/.

Sibling skill: nextjs-locale-monorepo — the same behaviour factored into a shared workspace package for multi-app repos. Keep the two in sync.

The behaviour (the spec both skills implement)