Step 2 (i18n): $localize sweep + JA_NEE dedup (M3, M4)

Wrap every user-facing Dutch string in Angular's first-party i18n — `i18n`/
`i18n-<attr>` in templates, `$localize` in TS (value-objects, machines, commands,
label constants, shared-component defaults). Source locale stays nl; a second
locale is now a translation file, not a code change.

- M3: ~145 strings localized with stable @@ ids across registratie,
  herregistratie, auth, shared/ui, shared/layout. Skipped: showcase, debug-state,
  scenario interceptor, generated client, specs/stories, raw status enum tags,
  internal parse* diagnostics.
- M4: single shared JA_NEE (localized labels) in radio-group; both wizard copies
  removed.

Gate green: lint, check:tokens, build, test 77/77.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/auth/infrastructure/digid.adapter.ts

@@ -9,7 +9,7 @@ export class DigidAdapter {
   // Swap for a real OIDC redirect flow when there's a backend.
   async authenticate(bsn: string): Promise<Result<string, Session>> {
     const t = bsn.trim();
-    if (!/^\d{9}$/.test(t)) return err('Voer een geldig BSN van 9 cijfers in.');
+    if (!/^\d{9}$/.test(t)) return err($localize`:@@validation.bsn:Voer een geldig BSN van 9 cijfers in.`);
     return ok({ bsn: t, naam: 'Dr. A. (Anna) de Vries' });
   }
 }