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/auth/ui/login-form/login-form.component.ts

@@ -0,0 +1,31 @@
+import { Component, output } 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';
+
+/** Organism: DigiD-style mock login. No real auth — just composes atoms/molecules. */
+@Component({
+  selector: 'app-login-form',
+  imports: [FormsModule, FormFieldComponent, TextInputComponent, ButtonComponent],
+  template: `
+    <form (ngSubmit)="submit.emit(bsn)">
+      <app-form-field label="BSN" fieldId="bsn" description="9 cijfers (demo: vul iets in)">
+        <app-text-input inputId="bsn" [(ngModel)]="bsn" name="bsn" placeholder="123456789" />
+      </app-form-field>
+
+      <app-form-field label="Wachtwoord" fieldId="pw">
+        <app-text-input inputId="pw" type="password" [(ngModel)]="password" name="pw" />
+      </app-form-field>
+
+      <div style="margin-top:1rem">
+        <app-button type="submit" variant="primary">Inloggen met DigiD</app-button>
+      </div>
+    </form>
+  `,
+})
+export class LoginFormComponent {
+  bsn = '';
+  password = '';
+  submit = output<string>();
+}