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/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} />