## Summary
Continue ADR-0019: replace the `/accessibility` + `/accessibilite` twin routes with a single canonical route whose content is i18n-marked in the template. The per-locale build (en/fr) already inlines the right copy — the route-data + `copy()` service indirection is no longer carrying its weight.
## What changes
- **`AccessibilityStatement`** loses its `ActivatedRoute` injection, the `Lang` discriminator, and the `COPY` lookup table. The component is now a plain shell over the template.
- **`accessibility.html`** carries the title + intro + status panel as `i18n="@@page.accessibility.*"` markers. Six new trans-units in [`messages.fr.xlf`](apps/portal-shell/src/locale/messages.fr.xlf) provide the French copy — verbatim from the old `COPY.fr` block, so the page reads the same in FR as before.
- **`app.routes.ts`** declares the single canonical route at `path: 'accessibility'` and keeps `/accessibilite` alive as a `redirectTo: 'accessibility'`. Drops `data: { lang: ... }` — no longer consumed.
- **`footer.html`** collapses the dual link into one i18n-marked link (`@@footer.accessibilityLink`). EN bundle reads "Accessibility statement"; FR bundle reads "Déclaration d'accessibilité".
## Decision worth flagging
The path stays in English across both locales for now: `/en/accessibility` and `/fr/accessibility`. Translating route *segments* (`/fr/declaration-d-accessibilite`) needs either a custom URL serializer or per-locale route trees — not worth the complexity at this scale. The page title and the link label already differ per locale via i18n, which is what's actually visible to users.
The historical `/accessibilite` path keeps working via the route-level redirect. Drops out of the codebase once analytics confirm no traffic reaches it.
## Test plan
- [x] `pnpm exec nx run-many -t lint test build --projects=portal-shell` — green. **35 / 35 specs** (was 36; the obsolete `lang`-fallback test is removed).
- [x] Production build emits both locales. FR bundle contains `Statut`, `Déclaration`, the FR intro / panel bodies. No leftover English on swept strings.
- [x] `extract-i18n` clean (49 unique units now: +5 for `page.accessibility.*` + `footer.accessibilityLink`, −0; the old route-data `lang` markers were not i18n).
- [ ] Manual: serve-static then `/en/accessibility` and `/fr/accessibility` render their respective content; `/fr/accessibilite` 301-redirects to `/fr/accessibility`.
- [ ] Manual: footer shows one link, locale-aware ("Accessibility statement" / "Déclaration d'accessibilité").
- [ ] Manual: browser tab title flips between bundles ("Accessibility statement · APF Portal" / "Déclaration d'accessibilité · Portail APF").
## What this PR explicitly does NOT do
- Translate the URL path segment (next ADR-only refinement if needed).
- Add the locale switcher in the footer — that's the next PR on the i18n track.
- Wire a CI gate on missing translations.
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Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #94
julien
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