feat(search): wire sort/dir/tagQ state into page.svelte and URL params

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

frontend/src/routes/+page.svelte

@@ -19,6 +19,9 @@ let to = $state(untrack(() => data.filters?.to || ''));
 let senderId = $state(untrack(() => data.filters?.senderId || ''));
 let receiverId = $state(untrack(() => data.filters?.receiverId || ''));
 let tagNames = $state<string[]>(untrack(() => data.filters?.tags || []));
+let sort = $state(untrack(() => data.filters?.sort || 'DATE'));
+let dir = $state(untrack(() => data.filters?.dir || 'desc'));
+let tagQ = $state(untrack(() => data.filters?.tagQ || ''));
 
 const hasAdvancedFilters = (filters: typeof data.filters) =>
 	(filters?.tags?.length ?? 0) > 0 ||
@@ -39,6 +42,9 @@ function triggerSearch() {
 	if (senderId) params.set('senderId', senderId);
 	if (receiverId) params.set('receiverId', receiverId);
 	if (tagNames) tagNames.forEach((tag) => params.append('tag', tag));
+	if (sort) params.set('sort', sort);
+	if (dir) params.set('dir', dir);
+	if (tagQ) params.set('tagQ', tagQ);
 	goto(`/?${params.toString()}`, { keepFocus: true, noScroll: true });
 }
 
@@ -66,6 +72,9 @@ $effect(() => {
 	senderId = data.filters?.senderId || '';
 	receiverId = data.filters?.receiverId || '';
 	tagNames = data.filters?.tags || [];
+	sort = data.filters?.sort || 'DATE';
+	dir = data.filters?.dir || 'desc';
+	tagQ = data.filters?.tagQ || '';
 	if (hasAdvancedFilters(data.filters)) showAdvanced = true;
 });
 
@@ -88,6 +97,9 @@ const showRightColumn = $derived(data.canWrite || (data.incompleteDocs?.length ?
 		bind:receiverId={receiverId}
 		bind:tagNames={tagNames}
 		bind:showAdvanced={showAdvanced}
+		bind:sort={sort}
+		bind:dir={dir}
+		bind:tagQ={tagQ}
 		initialSenderName={data.initialValues?.senderName}
 		initialReceiverName={data.initialValues?.receiverName}
 		onSearch={handleTextSearch}

frontend/src/routes/page.svelte.spec.ts

@@ -239,3 +239,27 @@ describe('Home page – error state', () => {
 		await page.screenshot({ path: 'test-results/screenshots/home-error.png' });
 	});
 });
+
+// ─── Sort controls ────────────────────────────────────────────────────────────
+
+describe('Home page – sort controls', () => {
+	it('pre-fills sort from filters.sort', async () => {
+		const data = {
+			...emptyData,
+			filters: { ...emptyData.filters, sort: 'TITLE', dir: 'asc', tagQ: '' }
+		};
+		render(Page, { data });
+		const select = page.getByRole('combobox');
+		await expect.element(select).toHaveValue('TITLE');
+	});
+
+	it('renders direction toggle with asc indicator when dir is asc', async () => {
+		const data = {
+			...emptyData,
+			filters: { ...emptyData.filters, sort: 'DATE', dir: 'asc', tagQ: '' }
+		};
+		render(Page, { data });
+		const btn = page.getByRole('button', { name: /aufsteigend/i });
+		await expect.element(btn).toBeInTheDocument();
+	});
+});