fix(journey-editor): selectedPersons change calls markDirty via $effect

Skip-first-run $effect tracks selectedPersons array length; any add/remove
after mount marks the editor dirty so the unsaved-warning fires on nav.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/geschichte/JourneyEditor.svelte

@@ -32,6 +32,7 @@ let { geschichte, onSubmit, submitting = false }: Props = $props();
 const unsaved = createUnsavedWarning();
 
 let title = $state(geschichte.title ?? '');
+
 let body = $state(geschichte.body ?? '');
 let status: 'DRAFT' | 'PUBLISHED' = $state(geschichte.status ?? 'DRAFT');
 let selectedPersons: PersonOption[] = $state(
@@ -64,6 +65,17 @@ const alreadyAddedIds = $derived(
 const canPublish = $derived(items.length > 0 && !titleEmpty);
 const showPublishedEmptyWarning = $derived(status === 'PUBLISHED' && items.length === 0);
 
+// Skip the initial run so mounting with pre-existing persons doesn't mark dirty.
+let _personEffectMounted = false;
+$effect(() => {
+	void selectedPersons.length;
+	if (!_personEffectMounted) {
+		_personEffectMounted = true;
+		return;
+	}
+	unsaved.markDirty();
+});
+
 let listEl: HTMLElement | null = $state(null);
 let editorColEl: HTMLElement | null = $state(null);
 

frontend/src/lib/geschichte/JourneyEditor.svelte.spec.ts

@@ -678,6 +678,44 @@ describe('JourneyEditor — unsaved warning banner', () => {
 	});
 });
 
+describe('JourneyEditor — selectedPersons marks dirty', () => {
+	function getNavCallback() {
+		const calls = vi.mocked(beforeNavigate).mock.calls;
+		const [callback] = calls[calls.length - 1];
+		return (cancel = vi.fn()) => {
+			(callback as (nav: { cancel: () => void; to: { url: URL } | null }) => void)({
+				cancel,
+				to: { url: new URL('http://localhost/geschichten') }
+			});
+			return cancel;
+		};
+	}
+
+	it('removing a person chip marks the editor dirty', async () => {
+		render(
+			JourneyEditor,
+			defaultProps({
+				geschichte: makeGeschichte({
+					persons: [{ id: 'p1', firstName: 'Anna', lastName: 'Schmidt' }]
+				})
+			})
+		);
+
+		// Confirm navigation is NOT blocked initially (clean state)
+		const triggerNav = getNavCallback();
+		expect(triggerNav()).not.toHaveBeenCalled();
+
+		// Remove the person chip (aria-label = m.comp_multiselect_remove() = "Entfernen")
+		await userEvent.click(page.getByRole('button', { name: m.comp_multiselect_remove() }));
+
+		// After person removal, navigation should be blocked
+		await vi.waitFor(() => {
+			const cancel = triggerNav();
+			expect(cancel).toHaveBeenCalled();
+		});
+	});
+});
+
 describe('JourneyEditor — person chips from GeschichteView', () => {
 	it('renders person names in the sidebar chips (PersonView carries no displayName)', async () => {
 		render(