Add branching intake wizard (derived steps + radio-group atom)

A second wizard demonstrating a BRANCHING flow: the visible steps are derived
from the answers by a pure `visibleSteps` function rather than stored, so
answering "buiten Nederland gewerkt? -> ja" or reporting few hours adds steps
and the progress denominator changes live. Same Elm-style store + RemoteData
patterns as the fixed wizard; answers persist to localStorage.

- intake.machine.ts: IntakeState union + Answers + visibleSteps + pure reduce (+spec)
- intake-wizard organism, intake.page, submit-intake command
- new radio-group atom (ControlValueAccessor) in shared/ui
- /intake route + dashboard link + concepts showcase section
- tighten Aantekening.type to a 'Specialisme' | 'Aantekening' union
- README + ARCHITECTURE updated

Verified live end-to-end (branches add steps 4->5->6, review, submit) with no
console errors; build, unit tests, and Storybook all green.

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

src/app/app.routes.ts

@@ -12,6 +12,7 @@ export const routes: Routes = [
       { path: 'dashboard', canActivate: [authGuard], loadComponent: () => import('@registratie/ui/dashboard.page').then(m => m.DashboardPage) },
       { path: 'registratie', canActivate: [authGuard], loadComponent: () => import('@registratie/ui/registration-detail.page').then(m => m.RegistrationDetailPage) },
       { path: 'herregistratie', canActivate: [authGuard], loadComponent: () => import('@herregistratie/ui/herregistratie.page').then(m => m.HerregistratiePage) },
+      { path: 'intake', canActivate: [authGuard], loadComponent: () => import('@herregistratie/ui/intake.page').then(m => m.IntakePage) },
       { path: 'concepts', loadComponent: () => import('./showcase/concepts.page').then(m => m.ConceptsPage) },
       { path: '**', redirectTo: 'login' },
     ],