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/registratie/ui/dashboard.page.ts

@@ -0,0 +1,72 @@
+import { Component, inject } from '@angular/core';
+import { PageShellComponent } from '@shared/layout/page-shell/page-shell.component';
+import { HeadingComponent } from '@shared/ui/heading/heading.component';
+import { LinkComponent } from '@shared/ui/link/link.component';
+import { AlertComponent } from '@shared/ui/alert/alert.component';
+import { SkeletonComponent } from '@shared/ui/skeleton/skeleton.component';
+import { DataRowComponent } from '@shared/ui/data-row/data-row.component';
+import { ASYNC } from '@shared/ui/async/async.component';
+import { RegistrationSummaryComponent } from '@registratie/ui/registration-summary/registration-summary.component';
+import { RegistrationTableComponent } from '@registratie/ui/registration-table/registration-table.component';
+import { BigProfileStore } from '@registratie/application/big-profile.store';
+
+@Component({
+  selector: 'app-dashboard-page',
+  imports: [
+    PageShellComponent, HeadingComponent, LinkComponent, AlertComponent, SkeletonComponent,
+    DataRowComponent, ...ASYNC, RegistrationSummaryComponent, RegistrationTableComponent,
+  ],
+  template: `
+    <app-page-shell heading="Mijn BIG-registratie">
+      @if (store.pendingHerregistratie()) {
+        <app-alert type="info">Uw herregistratie-aanvraag is in behandeling.</app-alert>
+      }
+
+      <!-- ONE state for two combined services (BIG-register + BRP). -->
+      <app-async [data]="store.profile()">
+        <ng-template appAsyncLoaded let-p>
+          <app-registration-summary [reg]="$any(p).registration" />
+          <div class="rhc-card rhc-card--default" style="margin-top:1rem">
+            <app-heading [level]="2">Persoonsgegevens (BRP)</app-heading>
+            <dl class="rhc-data-summary rhc-data-summary--row">
+              <app-data-row key="Straat" [value]="$any(p).person.adres.straat" />
+              <app-data-row key="Postcode" [value]="$any(p).person.adres.postcode" />
+              <app-data-row key="Woonplaats" [value]="$any(p).person.adres.woonplaats" />
+            </dl>
+          </div>
+        </ng-template>
+        <ng-template appAsyncLoading>
+          <app-skeleton height="2.5rem" [count]="6" />
+        </ng-template>
+      </app-async>
+
+      <div style="margin-top:2rem">
+        <app-heading [level]="2">Specialismen en aantekeningen</app-heading>
+        <app-async [data]="store.aantekeningen()">
+          <ng-template appAsyncLoaded let-r>
+            <app-registration-table [rows]="$any(r)" />
+          </ng-template>
+          <ng-template appAsyncLoading>
+            <app-skeleton height="2.5rem" [count]="3" />
+          </ng-template>
+          <ng-template appAsyncEmpty>
+            <p class="rhc-paragraph">U heeft nog geen specialismen of aantekeningen.</p>
+          </ng-template>
+        </app-async>
+      </div>
+
+      <p style="margin-top:2rem">
+        <app-link to="/registratie">Gegevens bekijken of een wijziging doorgeven →</app-link>
+      </p>
+      <p>
+        <app-link to="/herregistratie">Herregistratie aanvragen →</app-link>
+      </p>
+      <p>
+        <app-link to="/concepts">Functionele patronen (impossible states) →</app-link>
+      </p>
+    </app-page-shell>
+  `,
+})
+export class DashboardPage {
+  protected store = inject(BigProfileStore);
+}