[timneutkens]

Reverts #98715. Re-apply the i18n fix.

[github-actions]

Tests Passed

Commit: 077789d

[timneutkens]

[P1] Preserve inferred locales across Proxy rewrites

The new localePathWasInferred = false assignment in resolve-routes.ts treats every locale in a Proxy rewrite destination as explicit. However, server/web/adapter.ts already recreates same-host rewrite destinations with NextURL({ forceLocale: true }), which inserts the default/domain locale even when the Proxy destination was unlocalized.

Reproduction using this PR's fixture:

return NextResponse.rewrite(new URL('/plain/123', request.url))

From an unlocalized Proxy source pathname, this should render app/plain/[id] with id = '123'. Instead, the PR renders app/[lang]/[...slug] with lang = 'en-US' or 'nl-NL' and slug = ['plain', '123']. Without that localized catch-all, the request returns 404.

Confirmed on both configured locale domains in development and production with Webpack. The base routes both requests to app/plain/[id] correctly. The original 14 regression cases pass on this PR.

The resolver needs to distinguish adapter-inferred locale prefixes from explicit rewrite destinations before choosing literal App route matching. I am investigating a fix and adding coverage for unlocalized Proxy destinations.