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>

docs/project/backlog/WP-34-adres-phone-brp-readonly.md

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+# WP-34 — Adres: phone field + BRP address read-only
+
+Status: done
+Phase: 7 — refinements
+
+## Why
+
+The "Mijn gegevens" screen let the user *edit* their address (straat/postcode/woonplaats) and
+submit it as an adreswijziging. But the BRP (Basisregistratie Personen) is the authority for a
+person's address — you change it at the municipality, not in a register self-service portal.
+This WP corrects that: the address is shown **read-only** (rendered from the BRP data the
+screen already loads), and the editable/submittable contact detail becomes the **phone number**
+— the thing CIBG actually holds and the professional can update here.
+
+## Decisions (made while building — no spec existed; flagged for review)
+
+- **The adreswijziging form becomes a telefoonwijziging form.** Address is read-only display;
+  phone is the one editable field. Same single-step machine idiom (Model/Msg/pure reduce +
+  value object + submit command) — only the fields changed.
+- **New `Telefoonnummer` value object** (parse-don't-validate, lax Dutch format: 10 digits,
+  leading 0, `+31`→`0`, formatting stripped). Backend `RejectPhoneChange` re-validates as the
+  authority (ADR-0001); the FE check is UX-only. Replaces the old address/`RejectChangeRequest`.
+- **Phone starts empty.** There is no current-phone anywhere in BRP/seed/Person, so no
+  current-value round-trip was added (YAGNI) — the form submits a new/updated number. The
+  read-only BRP address gives the screen its context.
+- **Endpoint reused, contract narrowed.** `POST /change-requests` now takes `{ telefoon }`
+  (category `telefoonwijziging`); the typed client was regenerated (drift check clean).
+
+## Files
+
+- `registratie/domain/value-objects/telefoonnummer.ts` (+spec) — new value object.
+- `registratie/domain/change-request.machine.ts` (+spec) — Draft/Valid now `{ telefoon }`.
+- `registratie/infrastructure/change-request.adapter.ts` — sends `{ telefoon }`.
+- `registratie/ui/change-request-form/change-request-form.component.ts` (+story) — read-only
+  BRP address block + editable phone field; takes `brpAdres` input.
+- `registratie/ui/registration-detail.page.ts` — passes `profile()?.person?.adres`.
+- Backend: `Dtos.cs`, `Program.cs`, `SubmissionRules.cs` (+ RuleTests/EndpointTests/IdempotencyTests).
+- `src/locale/*` — new/changed `$localize` ids + English targets.
+
+## Acceptance criteria
+
+- [x] BRP address rendered read-only with a "change it at your municipality" note.
+- [x] Phone field with format validation (client instant + server authoritative).
+- [x] `npm run ci` green (lint, format, tokens, 332 FE tests, localized build, backend 122
+      tests, api-client drift clean after commit).