feat(registratie): WP-34 — phone field + BRP address read-only

Reshape the adreswijziging form into a contact-change form: the BRP address is
authoritative and shown read-only (you change it at the gemeente), and the phone
number becomes the editable/submittable field. New Telefoonnummer value object
(parse-don't-validate); backend RejectPhoneChange re-validates as authority.
POST /change-requests now carries { telefoon } (typed client regenerated).

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

src/app/registratie/infrastructure/change-request.adapter.ts

@@ -3,21 +3,18 @@ import { ApiClient } from '@shared/infrastructure/api-client';
 import { Valid } from '@registratie/domain/change-request.machine';
 
 /**
- * Infrastructure adapter for the adreswijziging POST (`/api/v1/change-requests`) —
- * the single place the network client lives for change requests, so the command
- * and the UI never touch `ApiClient`. Returns the server reference; the server
- * re-validates and is the authority.
+ * Infrastructure adapter for the telefoonwijziging POST (`/api/v1/change-requests`) —
+ * the single place the network client lives for contact changes, so the command
+ * and the UI never touch `ApiClient`. The BRP address is authoritative and not
+ * submitted (WP-34); only the phone number is. Returns the server reference; the
+ * server re-validates and is the authority.
  */
 @Injectable({ providedIn: 'root' })
 export class ChangeRequestAdapter {
   private client = inject(ApiClient);
 
   async changeRequest(data: Valid): Promise<string> {
-    const res = await this.client.changeRequests({
-      straat: data.straat,
-      postcode: data.postcode,
-      woonplaats: data.woonplaats,
-    });
+    const res = await this.client.changeRequests({ telefoon: data.telefoon });
     return res.referentie ?? '';
   }
 }