feat(bulk-edit): add BulkSelectionBar and Alle-X-editieren fast path

- BulkSelectionBar component: sticky bottom bar shown only when canWrite
  and selection is non-empty. Buttons meet WCAG 44px touch targets and
  iOS safe-area inset is honoured.
- Bar mounted on /documents and /enrich.
- Alle X editieren button on /documents replaces the selection with
  every UUID matching the active filter (via /api/documents/ids) and
  jumps to /documents/bulk-edit.

Refs #225

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

frontend/src/lib/components/document/BulkSelectionBar.svelte

@@ -0,0 +1,46 @@
+<script lang="ts">
+import { goto } from '$app/navigation';
+import { m } from '$lib/paraglide/messages.js';
+import { bulkSelectionStore } from '$lib/stores/bulkSelection.svelte';
+
+let { canWrite }: { canWrite: boolean } = $props();
+
+const count = $derived(bulkSelectionStore.size);
+
+function openBulkEdit() {
+	goto('/documents/bulk-edit');
+}
+
+function clearAll() {
+	bulkSelectionStore.clear();
+}
+</script>
+
+{#if canWrite && count > 0}
+	<div
+		data-testid="bulk-selection-bar"
+		class="fixed right-0 bottom-0 left-0 z-30 flex items-center justify-between border-t border-line bg-surface px-4 py-3 pb-[max(0.75rem,env(safe-area-inset-bottom))] shadow-[0_-2px_8px_rgba(0,0,0,0.06)] sm:px-6"
+	>
+		<span class="font-sans text-sm font-medium text-ink" data-testid="bulk-selection-count">
+			{m.bulk_edit_n_selected({ count })}
+		</span>
+		<div class="flex items-center gap-2">
+			<button
+				type="button"
+				onclick={clearAll}
+				class="inline-flex min-h-[44px] items-center px-4 py-2 font-sans text-sm font-medium text-ink-2 transition-colors hover:text-ink"
+				data-testid="bulk-clear-all"
+			>
+				{m.bulk_edit_clear_all()}
+			</button>
+			<button
+				type="button"
+				onclick={openBulkEdit}
+				class="inline-flex min-h-[44px] items-center bg-primary px-5 py-2 font-sans text-xs font-bold tracking-widest text-primary-fg uppercase transition-colors hover:bg-primary/90"
+				data-testid="bulk-edit-open"
+			>
+				{m.bulk_edit_button()}
+			</button>
+		</div>
+	</div>
+{/if}

frontend/src/lib/components/document/BulkSelectionBar.svelte.spec.ts

@@ -0,0 +1,49 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import { goto } from '$app/navigation';
+import BulkSelectionBar from './BulkSelectionBar.svelte';
+import { bulkSelectionStore } from '$lib/stores/bulkSelection.svelte';
+
+vi.mock('$app/navigation', () => ({ goto: vi.fn() }));
+
+afterEach(() => {
+	cleanup();
+	vi.mocked(goto).mockClear();
+	bulkSelectionStore.clear();
+});
+
+describe('BulkSelectionBar', () => {
+	it('does not render when canWrite is false', async () => {
+		bulkSelectionStore.add('a');
+		render(BulkSelectionBar, { canWrite: false });
+		await expect.element(page.getByTestId('bulk-selection-bar')).not.toBeInTheDocument();
+	});
+
+	it('does not render when selection is empty', async () => {
+		render(BulkSelectionBar, { canWrite: true });
+		await expect.element(page.getByTestId('bulk-selection-bar')).not.toBeInTheDocument();
+	});
+
+	it('renders with the current selection count', async () => {
+		bulkSelectionStore.add('a');
+		bulkSelectionStore.add('b');
+		render(BulkSelectionBar, { canWrite: true });
+		await expect.element(page.getByTestId('bulk-selection-count')).toHaveTextContent('2');
+	});
+
+	it('clear button empties the store', async () => {
+		bulkSelectionStore.add('a');
+		bulkSelectionStore.add('b');
+		render(BulkSelectionBar, { canWrite: true });
+		await page.getByTestId('bulk-clear-all').click();
+		expect(bulkSelectionStore.size).toBe(0);
+	});
+
+	it('Massenbearbeitung navigates to /documents/bulk-edit', async () => {
+		bulkSelectionStore.add('a');
+		render(BulkSelectionBar, { canWrite: true });
+		await page.getByTestId('bulk-edit-open').click();
+		expect(vi.mocked(goto)).toHaveBeenCalledWith('/documents/bulk-edit');
+	});
+});

frontend/src/routes/documents/+page.svelte

@@ -6,6 +6,8 @@ import { SvelteURLSearchParams } from 'svelte/reactivity';
 import SearchFilterBar from '../SearchFilterBar.svelte';
 import DocumentList from '../DocumentList.svelte';
 import Pagination from '$lib/components/Pagination.svelte';
+import BulkSelectionBar from '$lib/components/document/BulkSelectionBar.svelte';
+import { bulkSelectionStore } from '$lib/stores/bulkSelection.svelte';
 import * as m from '$lib/paraglide/messages.js';
 
 let { data } = $props();
@@ -138,6 +140,45 @@ $effect(() => {
 	}
 });
 
+let editingAll = $state(false);
+
+/**
+ * Fast path: replace the current selection with every document matching the
+ * active filter (across all pages) and jump to the bulk-edit screen. The
+ * /api/documents/ids endpoint is uncapped — chunking happens at PATCH time
+ * inside the bulk-edit page's save handler.
+ */
+async function editAllMatching() {
+	if (editingAll) return;
+	editingAll = true;
+	try {
+		const params = buildSearchParams({
+			q: data.q || '',
+			from: data.from || '',
+			to: data.to || '',
+			senderId: data.senderId || '',
+			receiverId: data.receiverId || '',
+			tags: data.tags || [],
+			sort: '',
+			dir: '',
+			tagQ: data.tagQ || '',
+			tagOp: (data.tagOp as 'AND' | 'OR') || 'AND'
+		});
+		params.delete('sort');
+		params.delete('dir');
+		const res = await fetch(`/api/documents/ids?${params.toString()}`);
+		if (!res.ok) {
+			editingAll = false;
+			return;
+		}
+		const ids: string[] = await res.json();
+		bulkSelectionStore.setAll(ids);
+		await goto('/documents/bulk-edit');
+	} finally {
+		editingAll = false;
+	}
+}
+
 // Keep local filter state in sync with server data after navigation completes.
 // Guard q: skip overwrite while the user is actively typing.
 $effect(() => {
@@ -181,6 +222,20 @@ $effect(() => {
 		onblur={() => (qFocused = false)}
 	/>
 
+	{#if data.canWrite && data.totalElements > 0}
+		<div class="mb-2 flex justify-end">
+			<button
+				type="button"
+				onclick={editAllMatching}
+				disabled={editingAll}
+				class="inline-flex items-center gap-1 text-sm font-medium text-ink-2 transition-colors hover:text-ink disabled:opacity-50"
+				data-testid="bulk-edit-all-x"
+			>
+				{m.bulk_edit_all_x({ count: data.totalElements })}
+			</button>
+		</div>
+	{/if}
+
 	<DocumentList
 		items={data.items}
 		total={data.totalElements}
@@ -192,3 +247,5 @@ $effect(() => {
 
 	<Pagination page={data.pageNumber} totalPages={data.totalPages} makeHref={buildPageHref} />
 </main>
+
+<BulkSelectionBar canWrite={data.canWrite} />

frontend/src/routes/enrich/+page.svelte

@@ -99,3 +99,5 @@ const canWrite = $derived(data.canWrite);
 		</div>
 	{/if}
 </div>
+
+<BulkSelectionBar canWrite={canWrite} />