Lay down the i18n infrastructure ahead of the string sweep that
marks every UI label. No template or code changes yet — that comes
next.
What this commit does:
- Add `@angular/localize` as a direct dependency (it was a transitive
via the Angular metapackage; promoting it makes the `init` polyfill
resolvable).
- Configure the i18n block in `apps/portal-shell/project.json`:
source locale `en` (matches the project English-only rule, with
`baseHref: /en/`), one target locale `fr` (with
`baseHref: /fr/` and `translation` pointing at the seed XLF).
- Add `@angular/localize/init` to the `polyfills` array so the
runtime resolver is available before the app bootstraps.
- Add an `extract-i18n` Nx target that wraps Angular's
`@angular/build:extract-i18n` executor, dropping the source XLF
next to the translation files (`apps/portal-shell/src/locale/`).
- Enable `--localize` on the production build configuration. The
build now emits two folders — `dist/apps/portal-shell/browser/en/`
and `.../fr/` — each with the right `<html lang>` and `<base href>`.
- Seed an empty `messages.fr.xlf` (XLIFF 1.2 skeleton) so the build
is happy and the sweep PR can drop trans-units into it directly.
What is intentionally out of scope:
- String marking (the sweep PR — every existing UI label, then
populate `messages.fr.xlf` with translations).
- Locale switcher in the footer + `__Host-portal_locale` cookie + the
smart `/` redirect (lands once strings are translated and the user
can meaningfully switch).
- Collapsing `/accessibility` + `/accessibilite` into a single
localised route (lands with the sweep, since it requires marked
text + localized route paths).
- CI gate that fails the build on missing translations (lands when
there are translations to be missing).
Julien Gautier