fix(bulk-edit): pluralization, edit-mode CTA, error UI, real loading state

Elicit C1+C3 — bulk-selection count uses ICU-style plural keys
(bulk_edit_n_selected_one / _other) so n=1 reads as "1 Dokument" instead
of "1 Dokumente". Save CTA in edit mode reads "Anwenden" via the existing
bulk_edit_save_button key; UploadSaveBar grew an editMode prop. Multi-
chunk progress text is now visible (not aria-only).

Felix C2 — bulk-edit page wires the backend error code through
parseBackendError + getErrorMessage instead of falling back to a generic
internal_error.

Felix C5 — editAllMatching no longer swallows fetch failures: the button
shows an inline error with the backend-mapped message (e.g. when the
filter cap is exceeded).

Leonie C8 — replace the literal "…" loading glyph on /documents/bulk-edit
with a spinner + role=status + aria-live=polite + visible "Loading
documents…" text.

Leonie C9 — partial-failure card and bulk-edit page error card now use
the design-system `text-danger` / `bg-danger/10` / `border-danger/40`
tokens (dark-mode safe) instead of raw red palette values.

Leonie C10 + C13 — German plural fixed; EN badges retensed
("+ added" → "+ will be added", "replaced" → "will replace") to match
the future-tense intent of DE/ES.

Refs #225, PR #331

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

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

@@ -8,6 +8,7 @@ import DocumentList from '../DocumentList.svelte';
 import Pagination from '$lib/components/Pagination.svelte';
 import BulkSelectionBar from '$lib/components/document/BulkSelectionBar.svelte';
 import { bulkSelectionStore } from '$lib/stores/bulkSelection.svelte';
+import { getErrorMessage, parseBackendError } from '$lib/errors';
 import * as m from '$lib/paraglide/messages.js';
 
 let { data } = $props();
@@ -141,16 +142,18 @@ $effect(() => {
 });
 
 let editingAll = $state(false);
+let editAllError = $state<string | null>(null);
 
 /**
  * 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.
+ * /api/documents/ids endpoint is hard-capped (5000 results); on cap overflow
+ * the backend returns BULK_EDIT_TOO_MANY_IDS, which we surface inline.
  */
 async function editAllMatching() {
 	if (editingAll) return;
 	editingAll = true;
+	editAllError = null;
 	try {
 		const params = buildSearchParams({
 			q: data.q || '',
@@ -168,12 +171,15 @@ async function editAllMatching() {
 		params.delete('dir');
 		const res = await fetch(`/api/documents/ids?${params.toString()}`);
 		if (!res.ok) {
-			editingAll = false;
+			const backend = await parseBackendError(res);
+			editAllError = getErrorMessage(backend?.code);
 			return;
 		}
 		const ids: string[] = await res.json();
 		bulkSelectionStore.setAll(ids);
 		await goto('/documents/bulk-edit');
+	} catch {
+		editAllError = m.bulk_edit_all_x_failed();
 	} finally {
 		editingAll = false;
 	}
@@ -229,7 +235,7 @@ $effect(() => {
 	/>
 
 	{#if data.canWrite && data.totalElements > 0}
-		<div class="mb-2 flex justify-end">
+		<div class="mb-2 flex flex-col items-end gap-1">
 			<button
 				type="button"
 				onclick={editAllMatching}
@@ -239,6 +245,11 @@ $effect(() => {
 			>
 				{m.bulk_edit_all_x({ count: data.totalElements })}
 			</button>
+			{#if editAllError}
+				<p role="alert" class="text-xs text-danger" data-testid="bulk-edit-all-x-error">
+					{editAllError}
+				</p>
+			{/if}
 		</div>
 	{/if}
 

frontend/src/routes/documents/bulk-edit/+page.svelte

@@ -5,6 +5,7 @@ import { bulkSelectionStore } from '$lib/stores/bulkSelection.svelte';
 import BulkDocumentEditLayout, {
 	type BulkEditEntry
 } from '$lib/components/document/BulkDocumentEditLayout.svelte';
+import { getErrorMessage, parseBackendError } from '$lib/errors';
 import { m } from '$lib/paraglide/messages.js';
 
 let entries = $state<BulkEditEntry[]>([]);
@@ -14,6 +15,9 @@ let error = $state<string | null>(null);
 onMount(async () => {
 	const ids = Array.from(bulkSelectionStore.ids);
 	if (ids.length === 0) {
+		// Skip the loading flash on the empty-store redirect path — the user
+		// is bouncing back to /documents in the next tick.
+		loading = false;
 		await goto('/documents');
 		return;
 	}
@@ -24,14 +28,15 @@ onMount(async () => {
 			body: JSON.stringify({ ids })
 		});
 		if (!res.ok) {
-			error = m.error_internal_error();
+			const backend = await parseBackendError(res);
+			error = getErrorMessage(backend?.code);
 			loading = false;
 			return;
 		}
 		const summaries = (await res.json()) as BulkEditEntry[];
 		entries = summaries;
 	} catch {
-		error = m.error_internal_error();
+		error = getErrorMessage(undefined);
 	} finally {
 		loading = false;
 	}
@@ -43,9 +48,35 @@ onMount(async () => {
 </svelte:head>
 
 {#if loading}
-	<div class="flex h-full items-center justify-center p-12 text-sm text-ink-2">…</div>
+	<div
+		class="flex h-full items-center justify-center gap-3 p-12 text-sm text-ink-2"
+		role="status"
+		aria-live="polite"
+		data-testid="bulk-edit-loading"
+	>
+		<svg
+			class="h-5 w-5 animate-spin text-ink-3"
+			xmlns="http://www.w3.org/2000/svg"
+			fill="none"
+			viewBox="0 0 24 24"
+			aria-hidden="true"
+		>
+			<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"
+			></circle>
+			<path
+				class="opacity-75"
+				fill="currentColor"
+				d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"
+			></path>
+		</svg>
+		<span>{m.bulk_edit_loading()}</span>
+	</div>
 {:else if error}
-	<div class="m-6 rounded-sm border border-red-300 bg-red-50 p-4 text-sm text-red-700">
+	<div
+		role="alert"
+		class="m-6 rounded-sm border border-danger/40 bg-danger/10 p-4 text-sm text-danger"
+		data-testid="bulk-edit-page-error"
+	>
 		{error}
 	</div>
 {:else if entries.length > 0}