Restructure into DDD bounded contexts + functional state management

Reorganise from atomic-design-only folders into bounded contexts
(auth / registratie / herregistratie) over a shared kernel, each split into
domain / application / infrastructure / ui layers. Dependencies point inward;
the domain layer is framework-free. Path aliases (@shared/@auth/@registratie/
@herregistratie) make import direction explicit.

State management (Elm-style, native TS, no new deps):
- shared/application/store.ts — createStore(init, update): pure reducer + signal
- shared/application/remote-data.ts — add map/map2/map3/andThen combinators so
  several services fold into one RemoteData; <app-async> gains an [rd] input
- registratie/application/big-profile.store.ts — root singleton combining the
  BIG-register and BRP services via map2 into one state; holds the optimistic
  herregistratie flag shared with the dashboard
- herregistratie: machine gains a WizardMsg union + pure reduce; submit is a
  command that calls infra and dispatches the result, with optimistic update +
  rollback against the shared store
- auth: SessionStore + DigiD adapter + functional route guard; login establishes
  the session, protected routes use canActivate

Rich domain: registration.policy.ts (statusColor/label, herregistratie
eligibility, invariants); BigNummer/Postcode/Uren value objects with smart
constructors. status-badge is now domain-free (colour/label inputs).

Specs for the reducer, RemoteData combinators, and eligibility policy.

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

src/app/herregistratie/ui/herregistratie-wizard/herregistratie-wizard.component.ts

@@ -0,0 +1,108 @@
+import { Component, computed, inject, input } from '@angular/core';
+import { FormsModule } from '@angular/forms';
+import { FormFieldComponent } from '@shared/ui/form-field/form-field.component';
+import { TextInputComponent } from '@shared/ui/text-input/text-input.component';
+import { ButtonComponent } from '@shared/ui/button/button.component';
+import { AlertComponent } from '@shared/ui/alert/alert.component';
+import { SpinnerComponent } from '@shared/ui/spinner/spinner.component';
+import { createStore } from '@shared/application/store';
+import { BigProfileStore } from '@registratie/application/big-profile.store';
+import { WizardState, WizardMsg, Draft, initial, reduce } from '@herregistratie/domain/herregistratie.machine';
+import { submitHerregistratie } from '@herregistratie/application/submit-herregistratie';
+
+/** Organism: multi-step herregistratie wizard. ALL state lives in one signal
+    driven by the pure `reduce` function (see herregistratie.machine.ts) via an
+    Elm-style store. The UI just sends messages and folds over the state's tag —
+    no booleans like `submitting`/`submitted` that could contradict each other.
+    Submitting also flips an optimistic flag on the shared BigProfileStore, so
+    the dashboard shows "in behandeling" immediately. */
+@Component({
+  selector: 'app-herregistratie-wizard',
+  imports: [FormsModule, FormFieldComponent, TextInputComponent, ButtonComponent, AlertComponent, SpinnerComponent],
+  template: `
+    @switch (state().tag) {
+      @case ('Editing') {
+        <p class="rhc-paragraph" style="color:var(--rhc-color-grijs-700)">Stap {{ step() }} van 2</p>
+        <form (ngSubmit)="onPrimary()" style="max-width:28rem">
+          @if (step() === 1) {
+            <app-form-field label="Gewerkte uren (afgelopen 5 jaar)" fieldId="uren" [error]="errUren()">
+              <app-text-input inputId="uren" [ngModel]="draft().uren" (ngModelChange)="dispatch({ tag: 'SetField', key: 'uren', value: $event })"
+                name="uren" [invalid]="!!errUren()" placeholder="bijv. 4160" />
+            </app-form-field>
+            <app-button type="submit" variant="primary">Volgende</app-button>
+          } @else {
+            <app-form-field label="Behaalde nascholingspunten" fieldId="punten" [error]="errPunten()">
+              <app-text-input inputId="punten" [ngModel]="draft().punten" (ngModelChange)="dispatch({ tag: 'SetField', key: 'punten', value: $event })"
+                name="punten" [invalid]="!!errPunten()" placeholder="bijv. 200" />
+            </app-form-field>
+            <div style="display:flex;gap:0.5rem">
+              <app-button type="button" variant="secondary" (click)="dispatch({ tag: 'Back' })">Vorige</app-button>
+              <app-button type="submit" variant="primary">Herregistratie aanvragen</app-button>
+            </div>
+          }
+        </form>
+      }
+      @case ('Submitting') {
+        <app-spinner /> <span>Aanvraag wordt verwerkt…</span>
+      }
+      @case ('Submitted') {
+        <app-alert type="ok">Uw aanvraag tot herregistratie is ontvangen.</app-alert>
+      }
+      @case ('Failed') {
+        <app-alert type="error">Indienen mislukt: {{ failedError() }}</app-alert>
+        <div style="margin-top:1rem">
+          <app-button variant="secondary" (click)="onRetry()">Opnieuw proberen</app-button>
+        </div>
+      }
+    }
+  `,
+})
+export class HerregistratieWizardComponent {
+  private profile = inject(BigProfileStore);
+  private store = createStore<WizardState, WizardMsg>(initial, reduce);
+
+  /** Optional seed so Storybook / the showcase can mount any state directly. */
+  seed = input<WizardState>(initial);
+
+  protected state = this.store.model;
+  protected dispatch = this.store.dispatch;
+
+  private editing = computed(() => (this.state().tag === 'Editing' ? (this.state() as Extract<WizardState, { tag: 'Editing' }>) : null));
+  protected step = computed(() => this.editing()?.step ?? 1);
+  protected draft = computed<Draft>(() => this.editing()?.draft ?? { uren: '', punten: '' });
+  protected errUren = computed(() => this.editing()?.errors.uren ?? '');
+  protected errPunten = computed(() => this.editing()?.errors.punten ?? '');
+  protected failedError = computed(() => (this.state().tag === 'Failed' ? (this.state() as Extract<WizardState, { tag: 'Failed' }>).error : ''));
+
+  constructor() {
+    queueMicrotask(() => this.dispatch({ tag: 'Seed', state: this.seed() }));
+  }
+
+  onPrimary() {
+    const s = this.state();
+    if (s.tag !== 'Editing') return;
+    this.dispatch(s.step === 1 ? { tag: 'Next' } : { tag: 'Submit' });
+    this.runIfSubmitting();
+  }
+
+  onRetry() {
+    this.dispatch({ tag: 'Retry' });
+    this.runIfSubmitting();
+  }
+
+  /** The effect: when we entered Submitting, call the backend command, flip the
+      optimistic cross-page flag, then dispatch the result (and commit/rollback). */
+  private async runIfSubmitting() {
+    const s = this.state();
+    if (s.tag !== 'Submitting') return;
+    this.profile.beginHerregistratie();
+    const r = await submitHerregistratie(s.data);
+    if (r.ok) {
+      this.dispatch({ tag: 'SubmitConfirmed' });
+      this.profile.confirmHerregistratie();
+    } else {
+      this.dispatch({ tag: 'SubmitFailed', error: r.error });
+      this.profile.rollbackHerregistratie();
+    }
+  }
+}