feat(beheer): WP-32 — undo/redo for the stamdata table editor

Wire the WP-31 createHistory helper into StamdataStore: per-table undo/redo
over the edited rows, recording only real edits and restoring via the existing
Seed msg. Ctrl/Cmd+Z / +Shift+Z, deferring to native text-undo inside grid
cell inputs.

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

src/app/beheer/ui/stamdata-table-editor/stamdata-table-editor.component.ts

@@ -163,6 +163,12 @@ interface DisplayRow {
 
     @if (!previewing()) {
       <div class="footer">
+        <app-button variant="subtle" [disabled]="!canUndo()" (click)="undo.emit()">{{
+          undoLabel
+        }}</app-button>
+        <app-button variant="subtle" [disabled]="!canRedo()" (click)="redo.emit()">{{
+          redoLabel
+        }}</app-button>
         <app-button variant="secondary" (click)="rowAdded.emit()">{{ addRowLabel }}</app-button>
         <span class="counts">{{ countsLabel() }}</span>
         <app-button variant="primary" [disabled]="!canDownload()" (click)="download.emit()">{{
@@ -180,6 +186,8 @@ export class StamdataTableEditorComponent {
   counts = input.required<ChangeCounts>();
   previewDate = input('');
   canDownload = input(false);
+  canUndo = input(false);
+  canRedo = input(false);
   tables = input<readonly StamTable[]>([]);
   selectedTableId = input<string | null>(null);
 
@@ -189,6 +197,8 @@ export class StamdataTableEditorComponent {
   rowRemoved = output<number>();
   previewDateChanged = output<string>();
   download = output<void>();
+  undo = output<void>();
+  redo = output<void>();
 
   protected previewing = computed(() => this.previewDate() !== '');
 
@@ -224,6 +234,8 @@ export class StamdataTableEditorComponent {
   protected previewNote = $localize`:@@beheer.previewNote:Voorbeeld: alleen de rijen die op deze datum geldig zijn. Bewerken staat uit.`;
   protected actionsLabel = $localize`:@@beheer.actions:Acties`;
   protected removeLabel = $localize`:@@beheer.remove:Verwijderen`;
+  protected undoLabel = $localize`:@@beheer.undo:Ongedaan maken`;
+  protected redoLabel = $localize`:@@beheer.redo:Opnieuw uitvoeren`;
   protected addRowLabel = $localize`:@@beheer.addRow:Rij toevoegen`;
   protected downloadLabel = $localize`:@@beheer.download:Download JSON`;
   protected applyHint = $localize`:@@beheer.applyHint:Wijzigingen worden als JSON-bestand gedownload en via een pull request toegepast — de build (CI) controleert ze.`;