Add registratie wizard, BFF dashboard-view, contracts/value-objects, and architecture docs

Checkpoint of in-progress work: the registration wizard (address prefill,
DUO diploma lookup, policy questions), decision-DTO contracts, parse-don't-
validate value objects, infrastructure adapters, plus CLAUDE.md and the
architecture/ADR docs.

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

src/app/shared/ui/form-field/form-field.component.ts

@@ -6,13 +6,13 @@ import { Component, input } from '@angular/core';
   selector: 'app-form-field',
   template: `
     <div class="rhc-form-field utrecht-form-field" [class.utrecht-form-field--invalid]="!!error()">
-      <label class="utrecht-form-label" [for]="fieldId()">{{ label() }}</label>
+      <label class="utrecht-form-label" [id]="fieldId() + '-label'" [for]="fieldId()">{{ label() }}</label>
       @if (description()) {
-        <div class="utrecht-form-field-description">{{ description() }}</div>
+        <div class="utrecht-form-field-description" [id]="fieldId() + '-desc'">{{ description() }}</div>
       }
       <ng-content />
       @if (error()) {
-        <div class="utrecht-form-field-error-message" role="alert">{{ error() }}</div>
+        <div class="utrecht-form-field-error-message" [id]="fieldId() + '-error'" role="alert">{{ error() }}</div>
       }
     </div>
   `,