feat(fp): WP-09 — pure-logic closure: dates + missing command specs

Consolidate four hand-rolled nl-NL date formatters (tasks.ts, aanvraag-
block, letter-preview, aanvraag-view -- one more than the WP found) into
one shared/kernel/datum.ts::formatDatumNl, spec-pinned and empty-safe.
Add the two missing command specs CLAUDE.md's testing rule calls for:
draft-sync.spec.ts (debounce coalescing + trailing-call + submit Result
shape, via fake timers) and submit-change-request.spec.ts. Remove the
unused RemoteData.map3 (updating the three docs that mentioned it); the
variant input on confirmation.component.ts was already gone. Documents
both stale-WP-text corrections in the backlog file.

This closes out backlog Phase 1 (FP/DDD core, WP-05..09).

src/app/registratie/domain/aanvraag-view.ts

@@ -1,3 +1,4 @@
+import { formatDatumNl } from '@shared/kernel/datum';
 import { Aanvraag, AanvraagStatus, AanvraagType } from './aanvraag';
 
 /** View-model mapping for an aanvraag: type → labels, status → label, and the fields
@@ -49,12 +50,6 @@ export interface AanvraagRow {
   status: string;
 }
 
-function formatNL(iso?: string): string {
-  return iso
-    ? new Date(iso).toLocaleDateString('nl-NL', { day: 'numeric', month: 'long', year: 'numeric' })
-    : '';
-}
-
 /** Fields for a submitted aanvraag's row in the dashboard "aanvragen" list (Concept
     has no row — it renders as a resumable melding, see aanvraag-block). */
 export function submittedRow(a: Aanvraag): AanvraagRow {
@@ -63,7 +58,9 @@ export function submittedRow(a: Aanvraag): AanvraagRow {
   const ref = referentie(s);
   if (ref) parts.push($localize`:@@aanvraag.row.ref:Referentie ${ref}:ref:`);
   if (a.submittedAt)
-    parts.push($localize`:@@aanvraag.row.ingediend:ingediend op ${formatNL(a.submittedAt)}:datum:`);
+    parts.push(
+      $localize`:@@aanvraag.row.ingediend:ingediend op ${formatDatumNl(a.submittedAt)}:datum:`,
+    );
   if (s.tag === 'InBehandeling' && s.manual)
     parts.push(
       $localize`:@@aanvraagBlock.manual:Uw aanvraag wordt handmatig beoordeeld in de backoffice.`,
@@ -88,7 +85,7 @@ export function detailRows(a: Aanvraag): { key: string; value: string }[] {
     },
     {
       key: $localize`:@@aanvraag.detail.ingediend:Ingediend op`,
-      value: a.submittedAt ? formatNL(a.submittedAt) : '—',
+      value: a.submittedAt ? formatDatumNl(a.submittedAt) : '—',
     },
   ];
   if (a.status.tag === 'Afgewezen') {

src/app/registratie/domain/tasks.ts

@@ -1,3 +1,4 @@
+import { formatDatumNl } from '@shared/kernel/datum';
 import { Registration } from './registration';
 import { herregistratieDeadline } from './registration.policy';
 
@@ -12,10 +13,6 @@ export interface PortalTask {
   actionLabel: string;
 }
 
-function formatNL(d: Date): string {
-  return d.toLocaleDateString('nl-NL', { day: 'numeric', month: 'long', year: 'numeric' });
-}
-
 /**
  * Derive the open tasks for a professional (pure). Eligibility is the server's
  * decision (`decisions.eligibleForHerregistratie`), passed in — the FE renders it,
@@ -33,7 +30,7 @@ export function tasksFromProfile(
     tasks.push({
       title: $localize`:@@task.herregistratie.title:Vraag uw herregistratie aan`,
       description: deadline
-        ? $localize`:@@task.herregistratie.deadline:Verleng uw registratie vóór ${formatNL(deadline)}:deadline:.`
+        ? $localize`:@@task.herregistratie.deadline:Verleng uw registratie vóór ${formatDatumNl(deadline)}:deadline:.`
         : $localize`:@@task.herregistratie.nodeadline:U kunt nu uw herregistratie aanvragen.`,
       to: '/herregistratie',
       actionLabel: $localize`:@@task.herregistratie.action:Herregistratie aanvragen`,