docs(transcription): explain why SEARCH_RESULT_LIMIT lives in the shared module

Round-4 polish from Felix (#1): SEARCH_RESULT_LIMIT only has one consumer
today (PersonMentionEditor), so it risked masquerading as shared. Add a
one-line rationale that the symmetry with MAX_QUERY_LENGTH and
SEARCH_DEBOUNCE_MS — keeping all @mention knobs in one file — is the
intentional motivation, not a missed inlining.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/nightly.yml

@@ -79,6 +79,7 @@ jobs:
           IMPORT_HOST_DIR=/srv/familienarchiv-staging/import
           POSTGRES_USER=archiv
           SENTRY_DSN=${{ secrets.SENTRY_DSN }}
+          VITE_SENTRY_DSN=${{ secrets.VITE_SENTRY_DSN }}
           EOF
 
       - name: Verify backend /import:ro mount is wired

backend/src/main/java/org/raddatz/familienarchiv/document/Document.java

@@ -25,11 +25,14 @@ import java.util.UUID;
 @NamedEntityGraph(name = "Document.full", attributeNodes = {
         @NamedAttributeNode("sender"),
         @NamedAttributeNode("receivers"),
-        @NamedAttributeNode("tags")
+        @NamedAttributeNode("tags"),
+        @NamedAttributeNode("trainingLabels")
 })
 @NamedEntityGraph(name = "Document.list", attributeNodes = {
         @NamedAttributeNode("sender"),
-        @NamedAttributeNode("tags")
+        @NamedAttributeNode("receivers"),
+        @NamedAttributeNode("tags"),
+        @NamedAttributeNode("trainingLabels")
 })
 @Entity
 @Table(name = "documents")

backend/src/main/java/org/raddatz/familienarchiv/document/transcription/TranscriptionBlockController.java

@@ -43,7 +43,7 @@ public class TranscriptionBlockController {
 
     @PostMapping
     @ResponseStatus(HttpStatus.CREATED)
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public TranscriptionBlock createBlock(
             @PathVariable UUID documentId,
             @Valid @RequestBody CreateTranscriptionBlockDTO dto,
@@ -53,7 +53,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/{blockId}")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public TranscriptionBlock updateBlock(
             @PathVariable UUID documentId,
             @PathVariable UUID blockId,
@@ -65,7 +65,7 @@ public class TranscriptionBlockController {
 
     @DeleteMapping("/{blockId}")
     @ResponseStatus(HttpStatus.NO_CONTENT)
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public void deleteBlock(
             @PathVariable UUID documentId,
             @PathVariable UUID blockId) {
@@ -73,7 +73,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/reorder")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public List<TranscriptionBlock> reorderBlocks(
             @PathVariable UUID documentId,
             @RequestBody ReorderTranscriptionBlocksDTO dto) {
@@ -82,7 +82,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/{blockId}/review")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public TranscriptionBlock reviewBlock(
             @PathVariable UUID documentId,
             @PathVariable UUID blockId,
@@ -92,7 +92,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/review-all")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public List<TranscriptionBlock> markAllBlocksReviewed(
             @PathVariable UUID documentId,
             Authentication authentication) {

docker-compose.prod.yml

@@ -252,6 +252,8 @@ services:
       OTEL_METRICS_EXPORTER: none
       MANAGEMENT_METRICS_TAGS_APPLICATION: Familienarchiv
       MANAGEMENT_TRACING_SAMPLING_PROBABILITY: ${MANAGEMENT_TRACING_SAMPLING_PROBABILITY:-0.1}
+      SENTRY_DSN: ${SENTRY_DSN:-}
+      LOGGING_STRUCTURED_FORMAT_CONSOLE: ecs
     networks:
       - archiv-net
     healthcheck:
@@ -266,6 +268,10 @@ services:
     build:
       context: ./frontend
       target: production
+      args:
+        # Vite build-time variable — baked into the JS bundle at build time.
+        # Empty default so deploys succeed before the secret is configured.
+        VITE_SENTRY_DSN: ${VITE_SENTRY_DSN:-}
     restart: unless-stopped
     depends_on:
       backend:

frontend/Dockerfile

@@ -16,6 +16,10 @@ CMD ["npm", "run", "dev"]
 # Compiles the SvelteKit Node-adapter output to /app/build.
 FROM node:20.19.0-alpine3.21 AS build
 WORKDIR /app
+# VITE_SENTRY_DSN is a build-time variable — Vite bakes it into the bundle.
+# Passed via docker-compose build.args; empty string disables the SDK.
+ARG VITE_SENTRY_DSN
+ENV VITE_SENTRY_DSN=$VITE_SENTRY_DSN
 COPY package.json package-lock.json ./
 RUN npm ci
 COPY . .

frontend/eslint.config.js

@@ -106,6 +106,31 @@ export default defineConfig(
 			]
 		}
 	},
+	{
+		// Forbid test fixtures (*.test-fixture.svelte) from being imported by
+		// production code. Tree-shaking keeps them out of the production bundle
+		// today (no route reaches them), but a lint rule makes the boundary
+		// explicit so an accidental autocomplete import in a route or component
+		// fails fast. Test files (*.spec.ts / *.test.ts) and the fixtures
+		// themselves are exempt — see the next block. Nora #2 on PR #629
+		// round 3.
+		files: ['**/*.svelte', '**/*.svelte.ts', '**/*.svelte.js', '**/*.ts'],
+		ignores: ['**/*.spec.ts', '**/*.test.ts', '**/*.test-fixture.svelte'],
+		rules: {
+			'no-restricted-imports': [
+				'error',
+				{
+					patterns: [
+						{
+							group: ['**/*.test-fixture.svelte'],
+							message:
+								'Test fixtures (*.test-fixture.svelte) are test-only — do not import from production code. Tracked by #637.'
+						}
+					]
+				}
+			]
+		}
+	},
 	{
 		plugins: { boundaries },
 		settings: {

frontend/messages/de.json

@@ -445,8 +445,12 @@
 	"person_mention_load_error": "Person konnte nicht geladen werden.",
 	"person_mention_loading": "Lade Person…",
 	"person_mention_popup_empty": "Keine Personen gefunden",
+	"person_mention_search_label": "Person suchen",
+	"person_mention_search_prompt": "Namen eingeben…",
 	"person_mention_btn_label": "Person verlinken",
 	"person_mention_create_new": "Neue Person anlegen",
+	"person_mention_results_count_singular": "1 Person gefunden",
+	"person_mention_results_count_plural": "{count} Personen gefunden",
 	"transcription_editor_aria_label": "Transkriptionstext",
 	"person_born_name_prefix": "geb.",
 	"page_title_home": "Archiv",
@@ -522,6 +526,7 @@
 	"notification_filter_unread": "Ungelesen",
 	"notification_filter_mention": "Erwähnung",
 	"notification_filter_reply": "Antwort",
+	"notification_error_generic": "Aktion fehlgeschlagen. Bitte versuche es erneut.",
 	"notification_mark_all_read_aria": "Alle Benachrichtigungen als gelesen markieren",
 	"notification_load_more": "Ältere laden",
 	"notification_empty_history": "Keine Benachrichtigungen",
@@ -633,6 +638,9 @@
 	"transcription_block_review": "Als geprüft markieren",
 	"transcription_block_unreview": "Markierung aufheben",
 	"transcription_reviewed_count": "{reviewed} von {total} geprüft",
+	"transcription_mark_all_reviewed": "Alle als fertig markieren",
+	"transcription_mark_all_reviewed_disabled": "Alle Blöcke sind bereits als fertig markiert",
+	"transcription_mark_all_reviewed_error": "Markierung fehlgeschlagen. Bitte versuchen Sie es erneut.",
 	"training_ocr_heading": "Kurrent-Erkennung trainieren",
 	"training_ocr_description": "Starte ein neues Training mit den bisher geprüften OCR-Blöcken, um die Erkennungsgenauigkeit für Kurrentschrift zu verbessern.",
 	"training_ocr_blocks_ready": "{blocks} geprüfte Blöcke bereit / {docs} Dokumente",

frontend/messages/en.json

@@ -445,8 +445,12 @@
 	"person_mention_load_error": "Could not load person.",
 	"person_mention_loading": "Loading person…",
 	"person_mention_popup_empty": "No persons found",
+	"person_mention_search_label": "Search for a person",
+	"person_mention_search_prompt": "Enter a name…",
 	"person_mention_btn_label": "Link person",
 	"person_mention_create_new": "Create new person",
+	"person_mention_results_count_singular": "1 person found",
+	"person_mention_results_count_plural": "{count} persons found",
 	"transcription_editor_aria_label": "Transcription text",
 	"person_born_name_prefix": "née",
 	"page_title_home": "Archive",
@@ -522,6 +526,7 @@
 	"notification_filter_unread": "Unread",
 	"notification_filter_mention": "Mention",
 	"notification_filter_reply": "Reply",
+	"notification_error_generic": "Action failed. Please try again.",
 	"notification_mark_all_read_aria": "Mark all notifications as read",
 	"notification_load_more": "Load older",
 	"notification_empty_history": "No notifications",
@@ -633,6 +638,9 @@
 	"transcription_block_review": "Mark as reviewed",
 	"transcription_block_unreview": "Unmark as reviewed",
 	"transcription_reviewed_count": "{reviewed} of {total} reviewed",
+	"transcription_mark_all_reviewed": "Mark all as reviewed",
+	"transcription_mark_all_reviewed_disabled": "All blocks are already marked as reviewed",
+	"transcription_mark_all_reviewed_error": "Failed to mark all as reviewed. Please try again.",
 	"training_ocr_heading": "Train Kurrent recognition",
 	"training_ocr_description": "Start a new training run using the reviewed OCR blocks to improve recognition accuracy for Kurrent script.",
 	"training_ocr_blocks_ready": "{blocks} reviewed blocks ready / {docs} documents",

frontend/messages/es.json

@@ -445,8 +445,12 @@
 	"person_mention_load_error": "No se pudo cargar la persona.",
 	"person_mention_loading": "Cargando persona…",
 	"person_mention_popup_empty": "No se encontraron personas",
+	"person_mention_search_label": "Buscar persona",
+	"person_mention_search_prompt": "Escribe un nombre…",
 	"person_mention_btn_label": "Vincular persona",
 	"person_mention_create_new": "Crear nueva persona",
+	"person_mention_results_count_singular": "1 persona encontrada",
+	"person_mention_results_count_plural": "{count} personas encontradas",
 	"transcription_editor_aria_label": "Texto de transcripción",
 	"person_born_name_prefix": "n.",
 	"page_title_home": "Archivo",
@@ -522,6 +526,7 @@
 	"notification_filter_unread": "No leídas",
 	"notification_filter_mention": "Mención",
 	"notification_filter_reply": "Respuesta",
+	"notification_error_generic": "La acción ha fallado. Por favor, inténtalo de nuevo.",
 	"notification_mark_all_read_aria": "Marcar todas las notificaciones como leídas",
 	"notification_load_more": "Cargar anteriores",
 	"notification_empty_history": "Sin notificaciones",
@@ -633,6 +638,9 @@
 	"transcription_block_review": "Marcar como revisado",
 	"transcription_block_unreview": "Desmarcar como revisado",
 	"transcription_reviewed_count": "{reviewed} de {total} revisados",
+	"transcription_mark_all_reviewed": "Marcar todo como revisado",
+	"transcription_mark_all_reviewed_disabled": "Todos los bloques ya están marcados como revisados",
+	"transcription_mark_all_reviewed_error": "Error al marcar como revisado. Intente de nuevo.",
 	"training_ocr_heading": "Entrenar reconocimiento Kurrent",
 	"training_ocr_description": "Inicia un nuevo entrenamiento con los bloques OCR revisados para mejorar la precisión de reconocimiento del script Kurrent.",
 	"training_ocr_blocks_ready": "{blocks} bloques revisados listos / {docs} documentos",

frontend/src/lib/activity/ChronikFuerDichBox.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+import { enhance } from '$app/forms';
 import * as m from '$lib/paraglide/messages.js';
 import { relativeTime } from '$lib/shared/utils/time';
 import type { NotificationItem } from '$lib/notification/notifications.svelte';
@@ -6,11 +7,13 @@ import { buildCommentHref } from '$lib/shared/discussion/commentDeepLink';
 
 interface Props {
 	unread: NotificationItem[];
-	onMarkRead: (n: NotificationItem) => void;
+	optimisticMarkRead: (id: string) => void;
-	onMarkAllRead: () => void;
+	optimisticMarkAllRead: () => void;
 }
 
-const { unread, onMarkRead, onMarkAllRead }: Props = $props();
+const { unread, optimisticMarkRead, optimisticMarkAllRead }: Props = $props();
+
+let errorMessage: string | null = $state(null);
 
 function verb(type: NotificationItem['type'], actor: string): string {
 	return type === 'REPLY'
@@ -24,6 +27,9 @@ function href(n: NotificationItem): string {
 </script>
 
 <section class="rounded-sm border border-line bg-surface p-5">
+	{#if errorMessage}
+		<p role="alert" class="px-4 py-2 text-sm text-red-600">{errorMessage}</p>
+	{/if}
 	{#if unread.length === 0}
 		<div data-testid="chronik-inbox-zero" class="flex flex-col items-center gap-3 py-6 text-center">
 			<svg
@@ -66,14 +72,28 @@ function href(n: NotificationItem): string {
 					{m.chronik_for_you_count({ count: unread.length })}
 				</span>
 			</div>
+			<form
+				action="/aktivitaeten?/mark-all-read"
+				method="POST"
+				use:enhance={() => {
+					errorMessage = null;
+					optimisticMarkAllRead();
+					return async ({ result, update }) => {
+						if (result.type === 'failure' || result.type === 'error') {
+							errorMessage = m.notification_error_generic();
+							await update({ reset: false, invalidateAll: false });
+						}
+					};
+				}}
+			>
 				<button
-				type="button"
+					type="submit"
 					data-testid="chronik-mark-all-read"
-				onclick={onMarkAllRead}
 					class="font-sans text-xs font-medium text-ink-3 transition-colors hover:text-ink"
 				>
 					{m.chronik_mark_all_read()}
 				</button>
+			</form>
 		</div>
 
 		<ul role="list" class="flex flex-col gap-2">
@@ -89,7 +109,7 @@ function href(n: NotificationItem): string {
 							aria-hidden="true"
 							class="mt-0.5 inline-flex h-6 w-6 shrink-0 items-center justify-center rounded-full bg-accent-bg font-sans text-xs font-bold text-accent"
 						>
-							{n.type === 'MENTION' ? '@' : '\u21A9'}
+							{n.type === 'MENTION' ? '@' : '↩'}
 						</span>
 						<div class="min-w-0 flex-1">
 							<p class="font-sans text-sm leading-snug text-ink">
@@ -100,11 +120,25 @@ function href(n: NotificationItem): string {
 							</p>
 						</div>
 					</a>
+					<form
+						action="/aktivitaeten?/dismiss-notification"
+						method="POST"
+						use:enhance={() => {
+							errorMessage = null;
+							optimisticMarkRead(n.id);
+							return async ({ result, update }) => {
+								if (result.type === 'failure' || result.type === 'error') {
+									errorMessage = m.notification_error_generic();
+									await update({ reset: false, invalidateAll: false });
+								}
+							};
+						}}
+					>
+						<input type="hidden" name="notificationId" value={n.id} />
 						<button
-						type="button"
+							type="submit"
 							data-testid="chronik-fuerdich-dismiss"
 							aria-label={m.chronik_mark_read_aria()}
-						onclick={() => onMarkRead(n)}
 							class="mt-0.5 shrink-0 rounded-sm p-1 text-ink-3 transition-colors hover:bg-muted hover:text-ink focus-visible:ring-2 focus-visible:ring-focus-ring focus-visible:outline-none"
 						>
 							<svg
@@ -119,6 +153,7 @@ function href(n: NotificationItem): string {
 								<path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" />
 							</svg>
 						</button>
+					</form>
 				</li>
 			{/each}
 		</ul>

frontend/src/lib/activity/ChronikFuerDichBox.svelte.spec.ts

@@ -5,7 +5,36 @@ import { page, userEvent } from 'vitest/browser';
 import ChronikFuerDichBox from './ChronikFuerDichBox.svelte';
 import type { NotificationItem } from '$lib/notification/notifications.svelte';
 
-afterEach(cleanup);
+const mockFormResult = vi.hoisted(() => ({ type: 'success' as string }));
+
+vi.mock('$app/forms', () => ({
+	enhance(
+		node: HTMLFormElement,
+		submit?: (opts: {
+			formData: FormData;
+		}) => (opts: {
+			result: { type: string; data?: Record<string, unknown> };
+			update: () => Promise<void>;
+		}) => Promise<void>
+	) {
+		const handler = async (e: Event) => {
+			e.preventDefault();
+			const cb = submit?.({ formData: new FormData(node) } as never);
+			if (typeof cb === 'function') {
+				await (
+					cb as (o: { result: typeof mockFormResult; update: () => Promise<void> }) => Promise<void>
+				)({ result: mockFormResult, update: async () => {} });
+			}
+		};
+		node.addEventListener('submit', handler);
+		return { destroy: () => node.removeEventListener('submit', handler) };
+	}
+}));
+
+afterEach(() => {
+	cleanup();
+	mockFormResult.type = 'success';
+});
 
 function notif(partial: Partial<NotificationItem>): NotificationItem {
 	return {
@@ -26,8 +55,8 @@ describe('ChronikFuerDichBox', () => {
 	it('renders inbox-zero state when there are no unread items', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		const zero = document.querySelector('[data-testid="chronik-inbox-zero"]');
 		expect(zero).not.toBeNull();
@@ -37,8 +66,8 @@ describe('ChronikFuerDichBox', () => {
 	it('links to the archived mentions in the inbox-zero state', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		const link = document.querySelector('a[href="/aktivitaeten?filter=fuer-dich"]');
 		expect(link).not.toBeNull();
@@ -47,8 +76,8 @@ describe('ChronikFuerDichBox', () => {
 	it('renders the count badge with correct total when unread exists', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [notif({ id: 'a' }), notif({ id: 'b' })],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		await expect.element(page.getByText('2 neu')).toBeInTheDocument();
 	});
@@ -56,8 +85,8 @@ describe('ChronikFuerDichBox', () => {
 	it('count badge has aria-live=polite when unread exists', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [notif({ id: 'a' })],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		// Wait for render
 		await expect.element(page.getByText('1 neu')).toBeInTheDocument();
@@ -69,8 +98,8 @@ describe('ChronikFuerDichBox', () => {
 	it('does not render the "Alle gelesen" button when there are no unread items', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		await expect.element(page.getByText('Keine neuen Erwähnungen')).toBeInTheDocument();
 		const all = document.querySelector('[data-testid="chronik-mark-all-read"]');
@@ -80,38 +109,38 @@ describe('ChronikFuerDichBox', () => {
 	it('renders the "Alle gelesen" button when unread exists', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [notif({ id: 'a' })],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		await expect.element(page.getByText('Alle gelesen')).toBeInTheDocument();
 	});
 
-	it('calls onMarkAllRead when the "Alle gelesen" button is clicked', async () => {
+	it('calls optimisticMarkAllRead when the "Alle gelesen" button is submitted', async () => {
-		const onMarkAllRead = vi.fn();
+		const optimisticMarkAllRead = vi.fn();
 		render(ChronikFuerDichBox, {
 			unread: [notif({ id: 'a' })],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead
+			optimisticMarkAllRead
 		});
 		await userEvent.click(page.getByText('Alle gelesen'));
-		expect(onMarkAllRead).toHaveBeenCalledTimes(1);
+		expect(optimisticMarkAllRead).toHaveBeenCalledTimes(1);
 	});
 
-	it('calls onMarkRead (and not navigation) when a per-item Dismiss button is clicked', async () => {
+	it('calls optimisticMarkRead with the notification id when its dismiss button is submitted', async () => {
-		const onMarkRead = vi.fn();
+		const optimisticMarkRead = vi.fn();
 		const n = notif({ id: 'xyz' });
 		render(ChronikFuerDichBox, {
 			unread: [n],
-			onMarkRead,
+			optimisticMarkRead,
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		const dismiss = document.querySelector(
 			'[data-testid="chronik-fuerdich-dismiss"]'
 		) as HTMLButtonElement | null;
 		expect(dismiss).not.toBeNull();
 		dismiss?.click();
-		expect(onMarkRead).toHaveBeenCalledTimes(1);
+		expect(optimisticMarkRead).toHaveBeenCalledTimes(1);
-		expect(onMarkRead.mock.calls[0][0]).toEqual(n);
+		expect(optimisticMarkRead.mock.calls[0][0]).toBe('xyz');
 	});
 
 	it('mention row href includes both commentId and annotationId when annotationId is present', async () => {
@@ -124,8 +153,8 @@ describe('ChronikFuerDichBox', () => {
 					annotationId: 'annot-9'
 				})
 			],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		const link = document.querySelector(
 			'a[href="/documents/doc-42?commentId=comment-7&annotationId=annot-9"]'
@@ -136,8 +165,8 @@ describe('ChronikFuerDichBox', () => {
 	it('Dismiss button is a sibling of the document link, never nested inside <a>', async () => {
 		render(ChronikFuerDichBox, {
 			unread: [notif({ id: 'x' })],
-			onMarkRead: vi.fn(),
+			optimisticMarkRead: vi.fn(),
-			onMarkAllRead: vi.fn()
+			optimisticMarkAllRead: vi.fn()
 		});
 		const dismiss = document.querySelector('[data-testid="chronik-fuerdich-dismiss"]');
 		expect(dismiss).not.toBeNull();
@@ -145,4 +174,22 @@ describe('ChronikFuerDichBox', () => {
 		// Prevents the senior-audience tap-drag bug flagged by Leonie.
 		expect(dismiss?.closest('a')).toBeNull();
 	});
+
+	it('shows an accessible error banner when the dismiss action returns a failure', async () => {
+		mockFormResult.type = 'failure';
+		render(ChronikFuerDichBox, {
+			unread: [notif({ id: 'err-1' })],
+			optimisticMarkRead: vi.fn(),
+			optimisticMarkAllRead: vi.fn()
+		});
+		const dismiss = document.querySelector(
+			'[data-testid="chronik-fuerdich-dismiss"]'
+		) as HTMLButtonElement | null;
+		expect(dismiss).not.toBeNull();
+		dismiss?.click();
+		// Allow microtask queue to flush
+		await new Promise((r) => setTimeout(r, 0));
+		const alert = document.querySelector('[role="alert"]');
+		expect(alert).not.toBeNull();
+	});
 });

frontend/src/lib/activity/ChronikFuerDichBox.svelte.test.ts

@@ -4,7 +4,36 @@ import { page } from 'vitest/browser';
 import ChronikFuerDichBox from './ChronikFuerDichBox.svelte';
 import type { NotificationItem } from '$lib/notification/notifications';
 
-afterEach(cleanup);
+const mockFormResult = vi.hoisted(() => ({ type: 'success' as string }));
+
+vi.mock('$app/forms', () => ({
+	enhance(
+		node: HTMLFormElement,
+		submit?: (opts: {
+			formData: FormData;
+		}) => (opts: {
+			result: { type: string; data?: Record<string, unknown> };
+			update: () => Promise<void>;
+		}) => Promise<void>
+	) {
+		const handler = async (e: Event) => {
+			e.preventDefault();
+			const cb = submit?.({ formData: new FormData(node) } as never);
+			if (typeof cb === 'function') {
+				await (
+					cb as (o: { result: typeof mockFormResult; update: () => Promise<void> }) => Promise<void>
+				)({ result: mockFormResult, update: async () => {} });
+			}
+		};
+		node.addEventListener('submit', handler);
+		return { destroy: () => node.removeEventListener('submit', handler) };
+	}
+}));
+
+afterEach(() => {
+	cleanup();
+	mockFormResult.type = 'success';
+});
 
 const mention = (overrides: Partial<NotificationItem> = {}): NotificationItem => ({
 	id: 'n-1',
@@ -22,7 +51,7 @@ const mention = (overrides: Partial<NotificationItem> = {}): NotificationItem =>
 describe('ChronikFuerDichBox', () => {
 	it('renders the inbox-zero state when there are no unread', async () => {
 		render(ChronikFuerDichBox, {
-			props: { unread: [], onMarkRead: () => {}, onMarkAllRead: () => {} }
+			props: { unread: [], optimisticMarkRead: () => {}, optimisticMarkAllRead: () => {} }
 		});
 
 		await expect.element(page.getByText(/keine neuen erwähnungen/i)).toBeVisible();
@@ -34,8 +63,8 @@ describe('ChronikFuerDichBox', () => {
 		render(ChronikFuerDichBox, {
 			props: {
 				unread: [mention(), mention({ id: 'n-2' }), mention({ id: 'n-3' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {}
+				optimisticMarkAllRead: () => {}
 			}
 		});
 
@@ -47,8 +76,8 @@ describe('ChronikFuerDichBox', () => {
 		render(ChronikFuerDichBox, {
 			props: {
 				unread: [mention({ id: 'n-m', type: 'MENTION' }), mention({ id: 'n-r', type: 'REPLY' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {}
+				optimisticMarkAllRead: () => {}
 			}
 		});
 
@@ -62,8 +91,8 @@ describe('ChronikFuerDichBox', () => {
 		render(ChronikFuerDichBox, {
 			props: {
 				unread: [mention({ actorName: 'Bertha' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {}
+				optimisticMarkAllRead: () => {}
 			}
 		});
 
@@ -76,8 +105,8 @@ describe('ChronikFuerDichBox', () => {
 		render(ChronikFuerDichBox, {
 			props: {
 				unread: [mention({ type: 'REPLY', actorName: 'Carl' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {}
+				optimisticMarkAllRead: () => {}
 			}
 		});
 
@@ -86,11 +115,11 @@ describe('ChronikFuerDichBox', () => {
 			.toBeVisible();
 	});
 
-	it('calls onMarkRead with the notification when its dismiss button is clicked', async () => {
+	it('calls optimisticMarkRead with the notification id when its dismiss button is clicked', async () => {
-		const onMarkRead = vi.fn();
+		const optimisticMarkRead = vi.fn();
 		const item = mention({ id: 'n-7' });
 		render(ChronikFuerDichBox, {
-			props: { unread: [item], onMarkRead, onMarkAllRead: () => {} }
+			props: { unread: [item], optimisticMarkRead, optimisticMarkAllRead: () => {} }
 		});
 
 		const dismiss = document.querySelector(
@@ -98,35 +127,55 @@ describe('ChronikFuerDichBox', () => {
 		) as HTMLElement;
 		dismiss.click();
 
-		expect(onMarkRead).toHaveBeenCalledWith(item);
+		expect(optimisticMarkRead).toHaveBeenCalledWith('n-7');
 	});
 
-	it('calls onMarkAllRead when the mark-all-read button is clicked', async () => {
+	it('calls optimisticMarkAllRead when the mark-all-read button is clicked', async () => {
-		const onMarkAllRead = vi.fn();
+		const optimisticMarkAllRead = vi.fn();
 		render(ChronikFuerDichBox, {
 			props: {
 				unread: [mention()],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead
+				optimisticMarkAllRead
 			}
 		});
 
 		const btn = document.querySelector('[data-testid="chronik-mark-all-read"]') as HTMLElement;
 		btn.click();
 
-		expect(onMarkAllRead).toHaveBeenCalledOnce();
+		expect(optimisticMarkAllRead).toHaveBeenCalledOnce();
 	});
 
 	it('builds a deep-link href to the comment for each notification', async () => {
 		render(ChronikFuerDichBox, {
 			props: {
 				unread: [mention({ documentId: 'doc-x', referenceId: 'ref-y', annotationId: null })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {}
+				optimisticMarkAllRead: () => {}
 			}
 		});
 
 		const link = document.querySelector('ul[role="list"] li a') as HTMLAnchorElement;
 		expect(link.getAttribute('href')).toContain('doc-x');
 	});
+
+	it('shows an accessible error banner when the dismiss action returns a failure', async () => {
+		mockFormResult.type = 'failure';
+		render(ChronikFuerDichBox, {
+			props: {
+				unread: [mention({ id: 'err-1' })],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {}
+			}
+		});
+
+		const dismiss = document.querySelector(
+			'[data-testid="chronik-fuerdich-dismiss"]'
+		) as HTMLElement;
+		dismiss.click();
+		// Allow microtask queue to flush
+		await new Promise((r) => setTimeout(r, 0));
+		const alert = document.querySelector('[role="alert"]');
+		expect(alert).not.toBeNull();
+	});
 });

frontend/src/lib/document/BulkDocumentEditLayout.svelte

@@ -17,6 +17,7 @@ import PdfViewer from '$lib/document/viewer/PdfViewer.svelte';
 import { bulkTitleFromFilename } from '$lib/document/filename';
 import type { Tag } from '$lib/tag/TagInput.svelte';
 import type { components } from '$lib/generated/api';
+import { withCsrf } from '$lib/shared/cookies';
 
 type Person = components['schemas']['Person'];
 
@@ -183,7 +184,10 @@ async function saveUpload() {
 		// FormData with per-chunk progress. Session cookie is sent automatically
 		// by the browser for same-origin requests.
 		try {
-			const res = await fetch('/api/documents/quick-upload', { method: 'POST', body: formData });
+			const res = await fetch(
+				'/api/documents/quick-upload',
+				withCsrf({ method: 'POST', body: formData })
+			);
 			const body = await res.json().catch(() => ({ errors: [] }));
 			const errorFilenames = new Set<string>(
 				(body.errors ?? []).map((err: { filename: string }) => err.filename)

frontend/src/lib/document/transcription/TranscriptionBlock.svelte.spec.ts

@@ -1,7 +1,7 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
-import TranscriptionBlockHost from './TranscriptionBlock.test-host.svelte';
+import TranscriptionBlockHost from './TranscriptionBlock.test-fixture.svelte';
 import type { ConfirmService } from '$lib/shared/services/confirm.svelte.js';
 
 afterEach(cleanup);

frontend/src/lib/document/transcription/TranscriptionEditView.svelte

@@ -6,6 +6,7 @@ import TranscribeCoachEmptyState from '$lib/shared/help/TranscribeCoachEmptyStat
 import type { PersonMention, TranscriptionBlockData } from '$lib/shared/types';
 import { createBlockAutoSave } from '$lib/document/transcription/useBlockAutoSave.svelte';
 import { createBlockDragDrop } from '$lib/document/transcription/useBlockDragDrop.svelte';
+import { withCsrf } from '$lib/shared/cookies';
 
 type Props = {
 	documentId: string;
@@ -49,6 +50,7 @@ let activeBlockId: string | null = $state(null);
 let localLabels: string[] = $derived.by(() => [...trainingLabels]);
 let listEl: HTMLElement | null = $state(null);
 let markingAllReviewed = $state(false);
+let markAllError = $state<string | null>(null);
 
 const sortedBlocks = $derived([...blocks].sort((a, b) => a.sortOrder - b.sortOrder));
 const hasBlocks = $derived(blocks.length > 0);
@@ -67,8 +69,11 @@ $effect(() => {
 async function handleMarkAllReviewed() {
 	if (!onMarkAllReviewed) return;
 	markingAllReviewed = true;
+	markAllError = null;
 	try {
 		await onMarkAllReviewed();
+	} catch {
+		markAllError = m.transcription_mark_all_reviewed_error();
 	} finally {
 		markingAllReviewed = false;
 	}
@@ -109,11 +114,14 @@ function handleDelete(blockId: string) {
 
 async function reorder(newOrder: string[]) {
 	try {
-		const res = await fetch(`/api/documents/${documentId}/transcription-blocks/reorder`, {
+		const res = await fetch(
+			`/api/documents/${documentId}/transcription-blocks/reorder`,
+			withCsrf({
 				method: 'PUT',
 				headers: { 'Content-Type': 'application/json' },
 				body: JSON.stringify({ blockIds: newOrder })
-		});
+			})
+		);
 		if (!res.ok) return;
 		const updated = await res.json();
 		for (const b of updated) {
@@ -169,7 +177,7 @@ async function handleLabelToggle(label: string) {
 					<button
 						onclick={handleMarkAllReviewed}
 						disabled={allReviewed || markingAllReviewed}
-						title={allReviewed ? 'Alle Blöcke sind bereits als fertig markiert' : undefined}
+						title={allReviewed ? m.transcription_mark_all_reviewed_disabled() : undefined}
 						class="flex min-h-[44px] items-center gap-1.5 rounded-sm px-3 font-sans text-xs font-medium text-brand-navy/80 transition-colors hover:text-brand-navy focus-visible:ring-2 focus-visible:ring-brand-navy disabled:opacity-40"
 					>
 						{#if markingAllReviewed}
@@ -207,7 +215,7 @@ async function handleLabelToggle(label: string) {
 								<path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7" />
 							</svg>
 						{/if}
-						Alle als fertig markieren
+						{m.transcription_mark_all_reviewed()}
 					</button>
 				{/if}
 			</div>
@@ -217,6 +225,31 @@ async function handleLabelToggle(label: string) {
 					style="width: {reviewProgress}%"
 				></div>
 			</div>
+			{#if markAllError}
+				<div
+					role="alert"
+					class="mt-1.5 flex items-center gap-2 rounded-sm border border-red-200 bg-red-50 px-3 py-2 font-sans text-sm text-red-700"
+				>
+					<span class="flex-1">{markAllError}</span>
+					<button
+						onclick={() => (markAllError = null)}
+						aria-label={m.comp_dismiss()}
+						class="flex min-h-[44px] min-w-[44px] items-center justify-center rounded text-red-600 hover:text-red-700 focus-visible:ring-2 focus-visible:ring-red-500"
+					>
+						<svg
+							class="h-4 w-4"
+							fill="none"
+							stroke="currentColor"
+							stroke-width="2"
+							viewBox="0 0 24 24"
+							xmlns="http://www.w3.org/2000/svg"
+							aria-hidden="true"
+						>
+							<path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" />
+						</svg>
+					</button>
+				</div>
+			{/if}
 		</div>
 		<div class="p-4">
 			<!-- svelte-ignore a11y_no_static_element_interactions -->

frontend/src/lib/document/transcription/TranscriptionEditView.svelte.spec.ts

@@ -3,6 +3,7 @@ import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
 import TranscriptionEditView from './TranscriptionEditView.svelte';
 import { createConfirmService, CONFIRM_KEY } from '$lib/shared/services/confirm.svelte.js';
+import { m } from '$lib/paraglide/messages.js';
 
 afterEach(cleanup);
 
@@ -312,14 +313,14 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 			onMarkAllReviewed: vi.fn().mockResolvedValue(undefined)
 		});
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.toBeInTheDocument();
 	});
 
 	it('does not show "Alle als fertig markieren" button when onMarkAllReviewed is not provided', async () => {
 		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2] });
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.not.toBeInTheDocument();
 	});
 
@@ -329,7 +330,7 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 			onMarkAllReviewed: vi.fn().mockResolvedValue(undefined)
 		});
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.toBeDisabled();
 	});
 
@@ -343,7 +344,7 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 		// userEvent.click() via Playwright CDP doesn't reliably trigger Svelte 5 onclick
 		// handlers when a TipTap editor is mounted in the same component tree.
 		const btn = (await page
-			.getByRole('button', { name: /Alle als fertig markieren/ })
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
 			.element()) as HTMLButtonElement;
 		btn.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
 		await vi.waitFor(() => expect(onMarkAllReviewed).toHaveBeenCalledTimes(1));
@@ -361,12 +362,83 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 
 		// Same CDP click workaround: dispatch from browser JS to reliably fire Svelte 5 onclick
 		const btnEl = (await page
-			.getByRole('button', { name: /Alle als fertig markieren/ })
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
 			.element()) as HTMLButtonElement;
 		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.toBeDisabled();
 		resolveMarkAll();
 	});
+
+	it('shows error message when onMarkAllReviewed callback rejects', async () => {
+		const onMarkAllReviewed = vi.fn().mockRejectedValue(new Error('INTERNAL_ERROR'));
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+		await expect
+			.element(page.getByRole('alert'))
+			.toHaveTextContent(m.transcription_mark_all_reviewed_error());
+	});
+
+	it('clears error when dismiss button is clicked', async () => {
+		const onMarkAllReviewed = vi.fn().mockRejectedValue(new Error('INTERNAL_ERROR'));
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+
+		const dismissEl = (await page
+			.getByRole('button', { name: m.comp_dismiss() })
+			.element()) as HTMLButtonElement;
+		dismissEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+
+		await expect.element(page.getByRole('alert')).not.toBeInTheDocument();
+	});
+
+	it('clears error on next successful markAllReviewed call', async () => {
+		const onMarkAllReviewed = vi
+			.fn()
+			.mockRejectedValueOnce(new Error('INTERNAL_ERROR'))
+			.mockResolvedValue(undefined);
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+		// Wait for the button to be re-enabled before the second click — ensures the first
+		// async rejection has fully settled and Svelte has flushed state changes
+		await expect
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
+			.not.toBeDisabled();
+
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+
+		await expect.element(page.getByRole('alert')).not.toBeInTheDocument();
+	});
+
+	it('re-enables button after markAllReviewed failure', async () => {
+		const onMarkAllReviewed = vi.fn().mockRejectedValue(new Error('INTERNAL_ERROR'));
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+
+		await expect
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
+			.not.toBeDisabled();
+	});
 });

frontend/src/lib/document/transcription/useBlockAutoSave.svelte.ts

@@ -1,5 +1,6 @@
 import { SvelteMap } from 'svelte/reactivity';
 import type { PersonMention } from '$lib/shared/types';
+import { withCsrf } from '$lib/shared/cookies';
 
 export type SaveState = 'idle' | 'saving' | 'saved' | 'fading' | 'error';
 
@@ -116,12 +117,15 @@ export function createBlockAutoSave({ saveFn, documentId }: Options) {
 		for (const [blockId, text] of pendingTexts) {
 			const mentions = pendingMentions.get(blockId) ?? [];
 			clearDebounce(blockId);
-			void fetch(`/api/documents/${documentId}/transcription-blocks/${blockId}`, {
+			void fetch(
+				`/api/documents/${documentId}/transcription-blocks/${blockId}`,
+				withCsrf({
 					method: 'PUT',
 					headers: { 'Content-Type': 'application/json' },
 					body: JSON.stringify({ text, mentionedPersons: mentions }),
 					keepalive: true
-			});
+				})
+			);
 			pendingTexts.delete(blockId);
 			pendingMentions.delete(blockId);
 		}

frontend/src/lib/document/transcription/useTranscriptionBlocks.svelte.test.ts

@@ -259,12 +259,15 @@ describe('createTranscriptionBlocks.markAllReviewed', () => {
 		expect(ctrl.blocks.every((b) => b.reviewed)).toBe(true);
 	});
 
-	it('is a no-op when PUT returns non-OK', async () => {
+	it('throws and leaves blocks unchanged when PUT returns non-OK', async () => {
 		const fetchImpl = vi.fn(async (url: RequestInfo | URL, init?: RequestInit) => {
 			const u = url.toString();
 			const method = init?.method ?? 'GET';
 			if (u.includes('/review-all') && method === 'PUT') {
-				return new Response('', { status: 500 });
+				return new Response(JSON.stringify({ code: 'INTERNAL_ERROR' }), {
+					status: 500,
+					headers: { 'Content-Type': 'application/json' }
+				});
 			}
 			return new Response(JSON.stringify([baseBlock({ id: 'b-1', reviewed: false })]), {
 				status: 200,
@@ -274,7 +277,26 @@ describe('createTranscriptionBlocks.markAllReviewed', () => {
 
 		const ctrl = createTranscriptionBlocks({ documentId: () => 'doc-1', fetchImpl });
 		await ctrl.load();
-		await ctrl.markAllReviewed();
+		await expect(ctrl.markAllReviewed()).rejects.toThrow('INTERNAL_ERROR');
+		expect(ctrl.blocks[0].reviewed).toBe(false);
+	});
+
+	it('throws INTERNAL_ERROR when PUT returns non-JSON body (e.g. nginx 502)', async () => {
+		const fetchImpl = vi.fn(async (url: RequestInfo | URL, init?: RequestInit) => {
+			const u = url.toString();
+			const method = init?.method ?? 'GET';
+			if (u.includes('/review-all') && method === 'PUT') {
+				return new Response('Bad Gateway', { status: 502 });
+			}
+			return new Response(JSON.stringify([baseBlock({ id: 'b-1', reviewed: false })]), {
+				status: 200,
+				headers: { 'Content-Type': 'application/json' }
+			});
+		});
+
+		const ctrl = createTranscriptionBlocks({ documentId: () => 'doc-1', fetchImpl });
+		await ctrl.load();
+		await expect(ctrl.markAllReviewed()).rejects.toThrow('INTERNAL_ERROR');
 		expect(ctrl.blocks[0].reviewed).toBe(false);
 	});
 });

frontend/src/lib/document/transcription/useTranscriptionBlocks.svelte.ts

@@ -2,6 +2,7 @@
    lastEditedAt's $derived are scope-local to one computation; they're never
    stored on $state. */
 import type { TranscriptionBlockData, PersonMention } from '$lib/shared/types';
+import { makeCsrfFetch } from '$lib/shared/cookies';
 import { saveBlockWithConflictRetry } from './saveBlockWithConflictRetry';
 import { BlockConflictResolvedError } from './blockConflictMerge';
 
@@ -41,7 +42,7 @@ export function createTranscriptionBlocks(
 	options: TranscriptionBlocksOptions
 ): TranscriptionBlocksController {
 	const { documentId } = options;
-	const fetchImpl = options.fetchImpl ?? fetch;
+	const fetchImpl = makeCsrfFetch(options.fetchImpl ?? fetch);
 
 	let blocks = $state<TranscriptionBlockData[]>([]);
 	let annotationReloadKey = $state(0);
@@ -119,7 +120,11 @@ export function createTranscriptionBlocks(
 		const res = await fetchImpl(`/api/documents/${documentId()}/transcription-blocks/review-all`, {
 			method: 'PUT'
 		});
-		if (!res.ok) return;
+		if (!res.ok) {
+			const body = await res.json().catch(() => ({}));
+			// Never render body.message — route through getErrorMessage() to prevent leaking backend internals
+			throw new Error((body as { code?: string })?.code ?? 'INTERNAL_ERROR');
+		}
 		const updated = (await res.json()) as { id: string; reviewed: boolean }[];
 		for (const b of updated) {
 			const existing = blocks.find((x) => x.id === b.id);

frontend/src/lib/notification/NotificationBell.svelte

@@ -1,10 +1,8 @@
 <script lang="ts">
 import { onMount, onDestroy } from 'svelte';
-import { goto } from '$app/navigation';
 import { m } from '$lib/paraglide/messages.js';
 import { clickOutside } from '$lib/shared/actions/clickOutside';
 import { notificationStore } from '$lib/notification/notifications.svelte';
-import { buildCommentHref } from '$lib/shared/discussion/commentDeepLink';
 import NotificationDropdown from './NotificationDropdown.svelte';
 
 let open = $state(false);
@@ -30,17 +28,6 @@ function closeDropdown() {
 	bellButtonEl?.focus();
 }
 
-async function handleMarkRead(notification: Parameters<typeof stream.markRead>[0]) {
-	await stream.markRead(notification);
-	const url = buildCommentHref(
-		notification.documentId,
-		notification.referenceId,
-		notification.annotationId
-	);
-	closeDropdown();
-	goto(url);
-}
-
 function handleKeydown(event: KeyboardEvent) {
 	if (event.key === 'Escape' && open) {
 		event.stopPropagation();
@@ -113,8 +100,8 @@ onDestroy(() => {
 	{#if open}
 		<NotificationDropdown
 			notifications={stream.notifications}
-			onMarkRead={handleMarkRead}
+			optimisticMarkRead={stream.optimisticMarkRead}
-			onMarkAllRead={stream.markAllRead}
+			optimisticMarkAllRead={stream.optimisticMarkAllRead}
 			onClose={closeDropdown}
 		/>
 	{/if}

frontend/src/lib/notification/NotificationBell.svelte.spec.ts

@@ -3,10 +3,18 @@ import { cleanup, render } from 'vitest-browser-svelte';
 import type { NotificationItem } from '$lib/notification/notifications';
 import NotificationBell from './NotificationBell.svelte';
 
-const gotoMock = vi.hoisted(() => vi.fn());
+vi.mock('$app/navigation', () => ({ goto: vi.fn(), beforeNavigate: vi.fn() }));
-vi.mock('$app/navigation', () => ({ goto: gotoMock, beforeNavigate: vi.fn() }));
+vi.mock('$app/forms', () => ({
+	enhance(node: HTMLFormElement, submit?: (opts: { formData: FormData }) => unknown) {
+		const handler = (e: Event) => {
+			e.preventDefault();
+			submit?.({ formData: new FormData(node) } as never);
+		};
+		node.addEventListener('submit', handler);
+		return { destroy: () => node.removeEventListener('submit', handler) };
+	}
+}));
 
-const mockMarkRead = vi.hoisted(() => vi.fn().mockResolvedValue(undefined));
 const mockNotificationList = vi.hoisted((): { value: NotificationItem[] } => ({ value: [] }));
 
 vi.mock('$lib/notification/notifications.svelte', () => ({
@@ -17,18 +25,17 @@ vi.mock('$lib/notification/notifications.svelte', () => ({
 		get unreadCount() {
 			return mockNotificationList.value.length;
 		},
-		markRead: mockMarkRead,
+		optimisticMarkRead: vi.fn(),
+		optimisticMarkAllRead: vi.fn(),
 		fetchNotifications: vi.fn().mockResolvedValue(undefined),
 		init: vi.fn(),
-		destroy: vi.fn(),
+		destroy: vi.fn()
-		markAllRead: vi.fn()
 	}
 }));
 
 afterEach(() => {
 	cleanup();
-	gotoMock.mockClear();
+	vi.clearAllMocks();
-	mockMarkRead.mockClear();
 	mockNotificationList.value = [];
 });
 
@@ -45,16 +52,6 @@ const makeNotification = (overrides: Partial<NotificationItem> = {}): Notificati
 	...overrides
 });
 
-async function openDropdownAndClickFirstNotification() {
-	const bellButton = document.querySelector<HTMLButtonElement>('button[aria-haspopup="true"]')!;
-	bellButton.click();
-	await vi.waitFor(() => {
-		expect(document.querySelector('[role="dialog"]')).not.toBeNull();
-	});
-	const notifButton = document.querySelector<HTMLButtonElement>('[role="list"] button')!;
-	notifButton.click();
-}
-
 describe('NotificationBell — cursor and tooltip', () => {
 	it('bell button has cursor-pointer class', async () => {
 		render(NotificationBell);
@@ -82,29 +79,3 @@ describe('NotificationBell — cursor and tooltip', () => {
 		expect(btn.getAttribute('aria-label')).toBe(btn.getAttribute('title'));
 	});
 });
-
-describe('NotificationBell', () => {
-	it('handleMarkRead navigates to URL including annotationId when notification has annotationId', async () => {
-		mockNotificationList.value = [makeNotification({ annotationId: 'annot-1' })];
-		render(NotificationBell);
-
-		await openDropdownAndClickFirstNotification();
-
-		await vi.waitFor(() => {
-			expect(gotoMock).toHaveBeenCalledWith(
-				'/documents/doc-1?commentId=ref-1&annotationId=annot-1'
-			);
-		});
-	});
-
-	it('handleMarkRead navigates to commentId-only URL when annotationId is absent', async () => {
-		mockNotificationList.value = [makeNotification({ annotationId: null })];
-		render(NotificationBell);
-
-		await openDropdownAndClickFirstNotification();
-
-		await vi.waitFor(() => {
-			expect(gotoMock).toHaveBeenCalledWith('/documents/doc-1?commentId=ref-1');
-		});
-	});
-});

frontend/src/lib/notification/NotificationDropdown.svelte

@@ -1,17 +1,21 @@
 <script lang="ts">
 import { goto } from '$app/navigation';
+import { enhance } from '$app/forms';
 import { m } from '$lib/paraglide/messages.js';
 import { relativeTime } from '$lib/shared/utils/time';
+import { buildCommentHref } from '$lib/shared/discussion/commentDeepLink';
 import type { NotificationItem } from '$lib/notification/notifications.svelte';
 
 type Props = {
 	notifications: NotificationItem[];
-	onMarkRead: (notification: NotificationItem) => void;
+	optimisticMarkRead: (id: string) => void;
-	onMarkAllRead: () => void;
+	optimisticMarkAllRead: () => void;
 	onClose: () => void;
 };
 
-let { notifications, onMarkRead, onMarkAllRead, onClose }: Props = $props();
+let { notifications, optimisticMarkRead, optimisticMarkAllRead, onClose }: Props = $props();
+
+let errorMessage = $state<string | null>(null);
 
 function handleViewAll() {
 	onClose(); // close first — avoids stale dropdown during navigation transition
@@ -31,16 +35,35 @@ function handleViewAll() {
 			{m.notification_bell_label()}
 		</span>
 		{#if notifications.length > 0}
+			<form
+				action="/aktivitaeten?/mark-all-read"
+				method="POST"
+				use:enhance={() => {
+					errorMessage = null;
+					optimisticMarkAllRead();
+					return async ({ result, update }) => {
+						if (result.type === 'failure' || result.type === 'error') {
+							errorMessage = (result as { data?: { error?: string } }).data?.error ?? m.notification_error_generic();
+							await update({ reset: false, invalidateAll: false });
+						}
+					};
+				}}
+			>
 				<button
-				type="button"
+					type="submit"
-				onclick={onMarkAllRead}
 					class="text-xs font-medium text-ink-3 transition-colors hover:text-ink"
 				>
 					{m.notification_mark_all_read()}
 				</button>
+			</form>
 		{/if}
 	</div>
 
+	<!-- Error banner (shown when a dismiss or mark-all action fails) -->
+	{#if errorMessage}
+		<p role="alert" class="px-4 py-2 text-sm text-red-600">{errorMessage}</p>
+	{/if}
+
 	<!-- Notification list -->
 	{#if notifications.length === 0}
 		<!-- Empty state -->
@@ -66,10 +89,35 @@ function handleViewAll() {
 		<ul role="list" class="max-h-[24rem] overflow-y-auto">
 			{#each notifications as notification (notification.id)}
 				<li>
+					<form
+						action="/aktivitaeten?/dismiss-notification"
+						method="POST"
+						class="contents"
+						use:enhance={() => {
+							errorMessage = null;
+							optimisticMarkRead(notification.id);
+							return async ({ result, update }) => {
+								if (result.type === 'failure' || result.type === 'error') {
+									errorMessage = (result as { data?: { error?: string } }).data?.error ?? m.notification_error_generic();
+									await update({ reset: false, invalidateAll: false });
+								} else {
+									// Navigate away — no need to update the store since we're leaving the page
+									onClose();
+									goto(
+										buildCommentHref(
+											notification.documentId,
+											notification.referenceId,
+											notification.annotationId
+										)
+									);
+								}
+							};
+						}}
+					>
+						<input type="hidden" name="notificationId" value={notification.id} />
 						<button
-						type="button"
+							type="submit"
-						onclick={() => onMarkRead(notification)}
+							class="flex w-full cursor-pointer items-start gap-3 border-b border-line px-4 py-3.5 text-left last:border-b-0 hover:bg-canvas
-						class="flex w-full cursor-pointer items-start gap-3 border-b border-line px-4 py-3 text-left last:border-b-0 hover:bg-canvas
 								{!notification.read ? 'bg-accent-bg/20' : ''}"
 						>
 							<!-- Type icon -->
@@ -127,6 +175,7 @@ function handleViewAll() {
 								></span>
 							{/if}
 						</button>
+					</form>
 				</li>
 			{/each}
 		</ul>

frontend/src/lib/notification/NotificationDropdown.svelte.test.ts

@@ -6,9 +6,38 @@ import NotificationDropdown from './NotificationDropdown.svelte';
 
 vi.mock('$app/navigation', () => ({ goto: vi.fn() }));
 
+// Configurable result for the enhance mock — tests that need failure set
+// mockFormResult.type = 'failure' before clicking.
+const mockFormResult = vi.hoisted(() => ({ type: 'success' as string }));
+
+// Invoke the SubmitFunction and always call the returned result callback with
+// mockFormResult so tests can exercise both success and failure branches.
+vi.mock('$app/forms', () => ({
+	enhance(
+		node: HTMLFormElement,
+		submit?: (opts: {
+			formData: FormData;
+		}) => (opts: {
+			result: { type: string; data?: Record<string, unknown> };
+			update: () => Promise<void>;
+		}) => Promise<void>
+	) {
+		const handler = async (e: Event) => {
+			e.preventDefault();
+			const cb = submit?.({ formData: new FormData(node) } as never);
+			if (typeof cb === 'function') {
+				await cb({ result: mockFormResult, update: async () => {} } as never);
+			}
+		};
+		node.addEventListener('submit', handler);
+		return { destroy: () => node.removeEventListener('submit', handler) };
+	}
+}));
+
 afterEach(() => {
 	cleanup();
 	vi.clearAllMocks();
+	mockFormResult.type = 'success'; // reset to default after each test
 });
 
 const makeNotification = (overrides: Record<string, unknown> = {}) => ({
@@ -29,8 +58,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -42,8 +71,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -55,8 +84,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -70,8 +99,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [makeNotification()],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -83,8 +112,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [makeNotification({ type: 'REPLY', actorName: 'Bert' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -98,8 +127,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [makeNotification({ type: 'MENTION', actorName: 'Clara' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -116,8 +145,8 @@ describe('NotificationDropdown', () => {
 					makeNotification({ id: 'n1', read: false }),
 					makeNotification({ id: 'n2', read: true })
 				],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -126,37 +155,100 @@ describe('NotificationDropdown', () => {
 		expect(unreadDots.length).toBe(1);
 	});
 
-	it('calls onMarkRead with the notification when an item is clicked', async () => {
+	it('each notification row is wrapped in a form posting to the dismiss action', async () => {
-		const onMarkRead = vi.fn();
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification({ id: 'n42' })],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		const form = document.querySelector('form[action="/aktivitaeten?/dismiss-notification"]');
+		expect(form).not.toBeNull();
+		expect(form?.getAttribute('method')).toBe('POST');
+	});
+
+	it('the dismiss form has a hidden notificationId input with the notification id', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification({ id: 'n42' })],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		const input = document.querySelector<HTMLInputElement>(
+			'form[action="/aktivitaeten?/dismiss-notification"] input[name="notificationId"]'
+		);
+		expect(input?.value).toBe('n42');
+	});
+
+	it('calls optimisticMarkRead with the notification id when a row is submitted', async () => {
+		const optimisticMarkRead = vi.fn();
 		const n = makeNotification({ id: 'n42', actorName: 'Anna' });
 		render(NotificationDropdown, {
 			props: {
 				notifications: [n],
-				onMarkRead,
+				optimisticMarkRead,
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
 
 		await page.getByRole('button', { name: /Anna hat auf deinen/i }).click();
 
-		expect(onMarkRead).toHaveBeenCalledWith(n);
+		expect(optimisticMarkRead).toHaveBeenCalledWith('n42');
 	});
 
-	it('calls onMarkAllRead when the mark-all-read button is clicked', async () => {
+	it('the mark-all-read control is a form posting to the mark-all-read action', async () => {
-		const onMarkAllRead = vi.fn();
 		render(NotificationDropdown, {
 			props: {
 				notifications: [makeNotification()],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead,
+				optimisticMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		const form = document.querySelector('form[action="/aktivitaeten?/mark-all-read"]');
+		expect(form).not.toBeNull();
+		expect(form?.getAttribute('method')).toBe('POST');
+	});
+
+	it('calls optimisticMarkAllRead when the mark-all-read button is submitted', async () => {
+		const optimisticMarkAllRead = vi.fn();
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification()],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead,
 				onClose: () => {}
 			}
 		});
 
 		await page.getByRole('button', { name: /alle gelesen/i }).click();
 
-		expect(onMarkAllRead).toHaveBeenCalledOnce();
+		expect(optimisticMarkAllRead).toHaveBeenCalledOnce();
+	});
+
+	it('shows a role=alert error banner when mark-all-read returns a failure', async () => {
+		mockFormResult.type = 'failure';
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification()],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await page.getByRole('button', { name: /alle gelesen/i }).click();
+
+		const alert = document.querySelector('[role="alert"]');
+		expect(alert).not.toBeNull();
 	});
 
 	it('calls onClose when the view-all button is clicked', async () => {
@@ -164,8 +256,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose
 			}
 		});
@@ -179,8 +271,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -193,12 +285,15 @@ describe('NotificationDropdown', () => {
 	it('calls onClose before navigating to /aktivitaeten', async () => {
 		const callOrder: string[] = [];
 		const onClose = vi.fn(() => callOrder.push('close'));
-		vi.mocked(goto).mockImplementation(() => callOrder.push('goto'));
+		vi.mocked(goto).mockImplementation(() => {
+			callOrder.push('goto');
+			return Promise.resolve();
+		});
 		render(NotificationDropdown, {
 			props: {
 				notifications: [],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose
 			}
 		});
@@ -212,8 +307,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [makeNotification({ id: 'm1', type: 'MENTION', actorName: 'Anna' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -225,8 +320,8 @@ describe('NotificationDropdown', () => {
 		render(NotificationDropdown, {
 			props: {
 				notifications: [makeNotification({ id: 'r1', type: 'REPLY', actorName: 'Bert' })],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
@@ -242,14 +337,78 @@ describe('NotificationDropdown', () => {
 					makeNotification({ id: 'n1', actorName: 'First' }),
 					makeNotification({ id: 'n2', actorName: 'Second' })
 				],
-				onMarkRead: () => {},
+				optimisticMarkRead: () => {},
-				onMarkAllRead: () => {},
+				optimisticMarkAllRead: () => {},
 				onClose: () => {}
 			}
 		});
 
-		const items = document.querySelectorAll('button[type="button"]');
+		const forms = document.querySelectorAll('form[action="/aktivitaeten?/dismiss-notification"]');
-		// At least 2 items + mark-all button
+		expect(forms.length).toBe(2);
-		expect(items.length).toBeGreaterThanOrEqual(2);
+	});
+
+	it('calls onClose and goto with the deep-link URL after a successful dismiss', async () => {
+		const onClose = vi.fn();
+		const n = makeNotification({
+			id: 'n42',
+			documentId: 'd1',
+			referenceId: 'c1',
+			annotationId: null,
+			actorName: 'Anna'
+		});
+		render(NotificationDropdown, {
+			props: {
+				notifications: [n],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {},
+				onClose
+			}
+		});
+
+		await page.getByRole('button', { name: /Anna hat auf deinen/i }).click();
+
+		expect(onClose).toHaveBeenCalledOnce();
+		expect(goto).toHaveBeenCalledWith('/documents/d1?commentId=c1');
+	});
+
+	it('does NOT call onClose or goto when the dismiss action returns a failure', async () => {
+		mockFormResult.type = 'failure';
+		const onClose = vi.fn();
+		const n = makeNotification({ id: 'n99', actorName: 'Bob' });
+		render(NotificationDropdown, {
+			props: {
+				notifications: [n],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {},
+				onClose
+			}
+		});
+
+		await page.getByRole('button', { name: /Bob hat auf deinen/i }).click();
+
+		expect(onClose).not.toHaveBeenCalled();
+		expect(goto).not.toHaveBeenCalled();
+	});
+
+	it('calls goto with annotationId appended when the notification has an annotationId', async () => {
+		const n = makeNotification({
+			id: 'n55',
+			documentId: 'd1',
+			referenceId: 'c1',
+			annotationId: 'a1',
+			actorName: 'Eva'
+		});
+		render(NotificationDropdown, {
+			props: {
+				notifications: [n],
+				optimisticMarkRead: () => {},
+				optimisticMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await page.getByRole('button', { name: /Eva hat auf deinen/i }).click();
+
+		expect(goto).toHaveBeenCalledWith('/documents/d1?commentId=c1&annotationId=a1');
 	});
 });

frontend/src/lib/notification/notifications.svelte.spec.ts

@@ -108,12 +108,46 @@ describe('notificationStore (singleton)', () => {
 		expect(notificationStore.unreadCount).toBe(1);
 	});
 
-	it('markAllRead resets unreadCount', async () => {
+	it('optimisticMarkRead marks the notification read and decrements unreadCount without fetching', () => {
-		mockFetch.mockResolvedValue(new Response(null, { status: 200 }));
+		notificationStore.init();
-		await notificationStore.markAllRead();
+		const notification = makeNotification({ id: 'sse-1', read: false });
+		lastEventSource!.simulate('notification', JSON.stringify(notification));
+		mockFetch.mockReset(); // clear the fetchUnreadCount call from init
 
-		expect(mockFetch).toHaveBeenCalledWith('/api/notifications/read-all', { method: 'POST' });
+		notificationStore.optimisticMarkRead('sse-1');
+
+		expect(notificationStore.notifications[0].read).toBe(true);
 		expect(notificationStore.unreadCount).toBe(0);
+		expect(mockFetch).not.toHaveBeenCalled();
+	});
+
+	it('optimisticMarkRead on an already-read notification does not decrement unreadCount below 0', () => {
+		notificationStore.init();
+		const notification = makeNotification({ id: 'sse-1', read: true });
+		lastEventSource!.simulate('notification', JSON.stringify(notification));
+
+		notificationStore.optimisticMarkRead('sse-1');
+
+		expect(notificationStore.unreadCount).toBe(0);
+	});
+
+	it('optimisticMarkAllRead resets unreadCount and marks all notifications read without fetching', () => {
+		notificationStore.init();
+		lastEventSource!.simulate(
+			'notification',
+			JSON.stringify(makeNotification({ id: 'n1', read: false }))
+		);
+		lastEventSource!.simulate(
+			'notification',
+			JSON.stringify(makeNotification({ id: 'n2', read: false }))
+		);
+		mockFetch.mockReset();
+
+		notificationStore.optimisticMarkAllRead();
+
+		expect(notificationStore.unreadCount).toBe(0);
+		expect(notificationStore.notifications.every((n) => n.read)).toBe(true);
+		expect(mockFetch).not.toHaveBeenCalled();
 	});
 });
 

frontend/src/lib/notification/notifications.svelte.ts

@@ -35,28 +35,19 @@ async function fetchUnreadCount(): Promise<void> {
 	}
 }
 
-async function markRead(notification: NotificationItem): Promise<void> {
+function optimisticMarkRead(id: string): void {
-	if (!notification.read) {
+	const notification = notifications.find((n) => n.id === id);
-		try {
+	if (notification && !notification.read) {
-			await fetch(`/api/notifications/${notification.id}/read`, { method: 'PATCH' });
 		notification.read = true;
 		unreadCount = Math.max(0, unreadCount - 1);
-		} catch (e) {
-			console.error('Failed to mark notification as read', e);
-		}
 	}
 }
 
-async function markAllRead(): Promise<void> {
+function optimisticMarkAllRead(): void {
-	try {
-		await fetch('/api/notifications/read-all', { method: 'POST' });
 	for (const n of notifications) {
 		n.read = true;
 	}
 	unreadCount = 0;
-	} catch (e) {
-		console.error('Failed to mark all notifications as read', e);
-	}
 }
 
 function init(): void {
@@ -123,8 +114,8 @@ export const notificationStore = {
 	},
 	fetchNotifications,
 	fetchUnreadCount,
-	markRead,
+	optimisticMarkRead,
-	markAllRead,
+	optimisticMarkAllRead,
 	init,
 	destroy
 };

frontend/src/lib/ocr/OcrTrainingCard.svelte

@@ -2,6 +2,7 @@
 import TrainingHistory from './TrainingHistory.svelte';
 import { m } from '$lib/paraglide/messages.js';
 import type { TrainingRun } from '$lib/ocr/training.js';
+import { withCsrf } from '$lib/shared/cookies';
 
 interface TrainingInfo {
 	availableBlocks?: number;
@@ -33,7 +34,7 @@ async function startTraining() {
 	successMessage = null;
 	errorMessage = null;
 	try {
-		const res = await fetch('/api/ocr/train', { method: 'POST' });
+		const res = await fetch('/api/ocr/train', withCsrf({ method: 'POST' }));
 		if (res.ok) {
 			successMessage = m.training_success();
 			setTimeout(() => {

frontend/src/lib/ocr/SegmentationTrainingCard.svelte

@@ -2,6 +2,7 @@
 import TrainingHistory from './TrainingHistory.svelte';
 import { m } from '$lib/paraglide/messages.js';
 import type { TrainingRun } from '$lib/ocr/training.js';
+import { withCsrf } from '$lib/shared/cookies';
 
 interface TrainingInfo {
 	availableSegBlocks?: number;
@@ -27,7 +28,7 @@ async function startTraining() {
 	training = true;
 	successMessage = null;
 	try {
-		const res = await fetch('/api/ocr/segtrain', { method: 'POST' });
+		const res = await fetch('/api/ocr/segtrain', withCsrf({ method: 'POST' }));
 		if (res.ok) {
 			successMessage = m.training_success();
 			setTimeout(() => {

frontend/src/lib/shared/cookies.ts

@@ -1,3 +1,46 @@
+/**
+ * Reads the XSRF-TOKEN cookie set by Spring Security's CookieCsrfTokenRepository.
+ * Returns null outside the browser or when the cookie is absent.
+ */
+export function getCsrfToken(): string | null {
+	if (typeof document === 'undefined') return null;
+	const match = document.cookie.match(/(?:^|;\s*)XSRF-TOKEN=([^;]+)/);
+	return match ? decodeURIComponent(match[1]) : null;
+}
+
+/**
+ * Merges the X-XSRF-TOKEN header into a RequestInit so Spring Security's
+ * CSRF filter accepts the request. Safe to call server-side (no-op when the
+ * cookie is absent).
+ */
+export function withCsrf(init?: RequestInit): RequestInit {
+	const token = getCsrfToken();
+	if (!token) return init ?? {};
+	const headers = new Headers(init?.headers);
+	headers.set('X-XSRF-TOKEN', token);
+	return { ...init, headers };
+}
+
+/**
+ * Wraps a fetch implementation so that every state-mutating call (POST, PUT,
+ * PATCH, DELETE) automatically includes the X-XSRF-TOKEN header. GET/HEAD
+ * requests pass through unchanged.
+ *
+ * Used to CSRF-protect client-side hooks that accept an injectable fetchImpl.
+ * In unit tests the injected mock is wrapped but getCsrfToken() returns null
+ * (no browser cookie), so no header is added and existing test expectations
+ * are unaffected.
+ */
+export function makeCsrfFetch(inner: typeof fetch): typeof fetch {
+	return (input: RequestInfo | URL, init?: RequestInit): Promise<Response> => {
+		const method = (init?.method ?? 'GET').toUpperCase();
+		if (['POST', 'PUT', 'PATCH', 'DELETE'].includes(method)) {
+			return inner(input, withCsrf(init));
+		}
+		return inner(input, init);
+	};
+}
+
 /**
  * Extracts the fa_session cookie value from a list of Set-Cookie response headers.
  *

frontend/src/lib/shared/discussion/MentionDropdown.svelte

@@ -2,7 +2,18 @@
 import type { components } from '$lib/generated/api';
 // eslint-disable-next-line boundaries/dependencies -- mention dropdown needs person date formatting; extract to shared if it becomes reusable
 import { formatLifeDateRange } from '$lib/person/personLifeDates';
+import { untrack } from 'svelte';
 import { m } from '$lib/paraglide/messages.js';
+// Layered defence cap on the @mention search query length (CWE-400
+// amplification). The <input maxlength> attribute below caps direct
+// user edits, but the editor-mirror path (Tiptap contenteditable -> mirror
+// $effect -> searchQuery) is not covered by `maxlength` since the
+// contenteditable has no such enforcement. Clipping at the mirror keeps
+// the cap honest from both paths. Tracked server-side separately.
+// Nora #1 on PR #629. Hoisted to mentionConstants.ts so the host editor
+// (PersonMentionEditor) can clip the inserted displayName to the same cap
+// — see Felix #3 on PR #629.
+import { MAX_QUERY_LENGTH } from './mentionConstants';
 
 type Person = components['schemas']['Person'];
 
@@ -17,7 +28,46 @@ type DropdownState = {
 	clientRect: (() => DOMRect | null) | null;
 };
 
-let { model }: { model: DropdownState } = $props();
+let {
+	model,
+	editorQuery = '',
+	onSearch = () => {}
+}: {
+	model: DropdownState;
+	/** Text typed after `@` in the host editor. Mirrors into the search input
+	 *  until the user takes manual ownership by typing into the input itself. */
+	editorQuery?: string;
+	onSearch?: (query: string) => void;
+} = $props();
+
+let searchQuery = $state(untrack(() => editorQuery.slice(0, MAX_QUERY_LENGTH)));
+let userHasEdited = $state(false);
+
+// Intent-revealing alias used by both the persistent aria-live announcer and
+// the visible empty-state copy. Folding the duplicated rule into one $derived
+// keeps the two branches in lockstep. Felix #3 on PR #629 round 4.
+const isQueryEmpty = $derived(searchQuery.trim() === '');
+
+// Mirror the editor's typed text until the user takes ownership.
+//
+// Why `$state + $effect` (not `$derived`): `searchQuery` is also written by
+// `bind:value` on the <input> below, so it needs to be a mutable `$state`.
+// A `$derived` would be read-only and would clobber direct user edits on
+// every editor keystroke. The `userHasEdited` latch pins ownership once the
+// user types into the input. Felix #1 on PR #629.
+$effect(() => {
+	if (!userHasEdited) {
+		searchQuery = editorQuery.slice(0, MAX_QUERY_LENGTH);
+	}
+});
+
+// Fire onSearch whenever the effective query changes — covers both the
+// editor mirror and direct input edits. This is the only place onSearch
+// fires; when the dropdown is unmounted, the effect is disposed and no
+// further fetches occur.
+$effect(() => {
+	onSearch(searchQuery);
+});
 
 // highlightedIndex must be both writable (keyboard handler mutates it) and
 // reset when `items` changes (so it never points past the end of a new list).
@@ -112,16 +162,70 @@ function selectItem(item: Person) {
 	unauthenticated users.
 -->
 <div
-	class="fixed z-50 w-72 overflow-hidden rounded-sm border border-line bg-surface shadow-lg"
+	class="fixed z-50 w-72 max-w-[calc(100vw-1rem)] overflow-hidden rounded-sm border border-line bg-surface shadow-lg"
 	role="listbox"
 	aria-label={m.person_mention_btn_label()}
 	style:top={position.top}
 	style:bottom={position.bottom}
 	style:left={position.left}
 >
+	<div class="border-b border-line px-3 py-2">
+		<label class="sr-only" for="mention-search">{m.person_mention_search_label()}</label>
+		<div class="flex items-center gap-2">
+			<svg
+				aria-hidden="true"
+				viewBox="0 0 24 24"
+				fill="none"
+				stroke="currentColor"
+				stroke-width="2"
+				class="h-5 w-5 shrink-0 text-ink-2"
+			>
+				<circle cx="11" cy="11" r="7" />
+				<path d="m20 20-3.5-3.5" stroke-linecap="round" />
+			</svg>
+			<input
+				id="mention-search"
+				type="search"
+				data-test-search-input
+				maxlength={MAX_QUERY_LENGTH}
+				class="min-h-[44px] w-full bg-transparent font-sans text-base text-ink placeholder:text-ink-3 focus:outline-none focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:ring-inset"
+				placeholder={m.person_mention_search_prompt()}
+				bind:value={searchQuery}
+				oninput={() => {
+					userHasEdited = true;
+				}}
+				onmousedown={(e) => e.stopPropagation()}
+			/>
+		</div>
+	</div>
+	<!--
+		Persistent aria-live region — lives ABOVE the conditional branches so the
+		element never unmounts when items transition between empty and populated.
+		VoiceOver in particular swallows announcements from freshly-mounted live
+		regions, and the previous (conditional-inside) markup silently dropped
+		the "N persons found" announcement when results populated. Leonie #3 on
+		PR #629 round 3.
+	-->
+	<p class="sr-only" aria-live="polite">
 		{#if model.items.length === 0}
-		<p class="px-3 py-2.5 font-sans text-sm text-ink-3">
+			{isQueryEmpty ? m.person_mention_search_prompt() : m.person_mention_popup_empty()}
-			{m.person_mention_popup_empty()}
+		{:else if model.items.length === 1}
+			{m.person_mention_results_count_singular()}
+		{:else}
+			{m.person_mention_results_count_plural({ count: model.items.length })}
+		{/if}
+	</p>
+	{#if model.items.length === 0}
+		<!--
+			Visible empty-state copy — visual-only. The persistent sr-only <p>
+			above is the sole AT announcer; this one is hidden from screen readers
+			via aria-hidden="true" so VoiceOver does not double-announce
+			(NVDA de-dups, VoiceOver does not). Leonie S-2 on PR #629 round 4.
+			Do NOT add an aria-live attribute here — that would re-introduce
+			the duplicate announcement.
+		-->
+		<p aria-hidden="true" class="px-3 py-2.5 font-sans text-sm text-ink-3">
+			{isQueryEmpty ? m.person_mention_search_prompt() : m.person_mention_popup_empty()}
 		</p>
 		<!--
 			Empty-state escape hatch — without it the transcriber has to close
@@ -132,7 +236,7 @@ function selectItem(item: Person) {
 		<a
 			href="/persons/new"
 			target="_blank"
-			rel="noopener"
+			rel="noopener noreferrer"
 			class="flex min-h-[44px] items-center gap-2 border-t border-line px-3 py-2.5 font-sans text-sm font-medium text-brand-navy hover:bg-canvas focus:bg-canvas focus:outline-none"
 			onmousedown={(e) => e.preventDefault()}
 		>

frontend/src/lib/shared/discussion/MentionDropdown.svelte.test.ts

@@ -1,22 +1,37 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
-import { page } from 'vitest/browser';
+import { page, userEvent } from 'vitest/browser';
+import { flushSync, mount, tick, unmount } from 'svelte';
 import MentionDropdown from './MentionDropdown.svelte';
+import MentionDropdownFixture from './MentionDropdown.test-fixture.svelte';
+import { m } from '$lib/paraglide/messages.js';
+import type { components } from '$lib/generated/api';
+
+type Person = components['schemas']['Person'];
 
 afterEach(cleanup);
 
-const makePerson = (id: string, name: string, overrides: Record<string, unknown> = {}) => ({
+const makePerson = (id: string, name: string, overrides: Partial<Person> = {}): Person => {
+	const parts = name.split(' ');
+	return {
 		id,
-	firstName: name.split(' ')[0] ?? null,
+		firstName: parts[0],
-	lastName: name.split(' ').slice(1).join(' ') || name,
+		lastName: parts.slice(1).join(' ') || name,
 		displayName: name,
-	birthYear: null as number | null,
+		personType: 'PERSON',
-	deathYear: null as number | null,
+		familyMember: false,
 		...overrides
-});
+	};
+};
 
-const baseModel = (overrides: Record<string, unknown> = {}) => ({
+type DropdownState = {
-	items: [] as ReturnType<typeof makePerson>[],
+	items: Person[];
+	command: (item: Person) => void;
+	clientRect: (() => DOMRect | null) | null;
+};
+
+const baseModel = (overrides: Partial<DropdownState> = {}): DropdownState => ({
+	items: [],
 	command: vi.fn(),
 	clientRect: () => new DOMRect(100, 100, 0, 24),
 	...overrides
@@ -29,14 +44,32 @@ describe('MentionDropdown', () => {
 		await expect.element(page.getByRole('listbox', { name: /person verlinken/i })).toBeVisible();
 	});
 
-	it('renders the empty placeholder when items is empty', async () => {
+	it('shows the "enter a name" prompt when the search field is empty', async () => {
 		render(MentionDropdown, { props: { model: baseModel() } });
 
-		await expect.element(page.getByText('Keine Personen gefunden')).toBeVisible();
+		// Scope to the visible empty-state <p> (text-ink-3) — the persistent
+		// sr-only aria-live region above also contains the same prompt copy.
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_search_prompt());
+		expect(visibleEmptyP!.textContent ?? '').not.toContain(m.person_mention_popup_empty());
+	});
+
+	it('shows "no persons found" when the search has a query but the list is empty', async () => {
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: 'WdG' } });
+
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_popup_empty());
+		expect(visibleEmptyP!.textContent ?? '').not.toContain(m.person_mention_search_prompt());
 	});
 
 	it('shows the create-new escape hatch link in the empty state', async () => {
-		render(MentionDropdown, { props: { model: baseModel() } });
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: 'unknown' } });
 
 		const link = (await page
 			.getByRole('link', { name: /neue person anlegen/i })
@@ -44,6 +77,7 @@ describe('MentionDropdown', () => {
 		expect(link.href).toContain('/persons/new');
 		expect(link.target).toBe('_blank');
 		expect(link.rel).toContain('noopener');
+		expect(link.rel).toContain('noreferrer');
 	});
 
 	it('renders one option per item when populated', async () => {
@@ -104,3 +138,315 @@ describe('MentionDropdown', () => {
 		expect(dropdown.style.left).toBe('123px');
 	});
 });
+
+// ─── Search input — Issue #380 ────────────────────────────────────────────────
+
+describe('MentionDropdown — search input', () => {
+	it('renders a search input pre-filled with the editorQuery prop', async () => {
+		render(MentionDropdown, {
+			props: { model: baseModel(), editorQuery: 'WdG' }
+		});
+
+		await expect.element(page.getByRole('searchbox')).toHaveValue('WdG');
+	});
+
+	it('exposes a data-test-search-input attribute for E2E selectors', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]');
+		expect(input).not.toBeNull();
+		expect((input as HTMLInputElement).type).toBe('search');
+	});
+
+	it('search input wrapper meets the 44px touch target (WCAG 2.2 AA)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLElement;
+		expect(input).not.toBeNull();
+		expect(input.className).toContain('min-h-[44px]');
+	});
+
+	it('renders a persistent aria-live="polite" region (does not remount on items transition; Leonie #3 on PR #629)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const listbox = document.querySelector('[role="listbox"]');
+		expect(listbox).not.toBeNull();
+		const live = listbox!.querySelector('p[aria-live="polite"]');
+		expect(live).not.toBeNull();
+		// Empty + empty-query → "Namen eingeben…" prompt
+		expect(live!.textContent ?? '').toContain(m.person_mention_search_prompt());
+	});
+
+	it('announces the result count in the persistent live region when items populate (Leonie #3 on PR #629)', async () => {
+		render(MentionDropdown, {
+			props: {
+				model: baseModel({
+					items: [
+						makePerson('p1', 'Anna Schmidt'),
+						makePerson('p2', 'Bert Meier'),
+						makePerson('p3', 'Carl Vogel')
+					]
+				})
+			}
+		});
+
+		const listbox = document.querySelector('[role="listbox"]');
+		expect(listbox).not.toBeNull();
+		const live = listbox!.querySelector('p[aria-live="polite"]');
+		expect(live).not.toBeNull();
+		// Populated → "3 Personen gefunden" (plural)
+		expect(live!.textContent ?? '').toContain('3');
+	});
+
+	it('announces the singular form when exactly one item is present (Sara #4 on PR #629)', async () => {
+		render(MentionDropdown, {
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt')]
+				})
+			}
+		});
+
+		const listbox = document.querySelector('[role="listbox"]');
+		expect(listbox).not.toBeNull();
+		const live = listbox!.querySelector('p[aria-live="polite"]');
+		expect(live).not.toBeNull();
+		// Singular branch — "1 Person gefunden" / "1 person found" / "1 persona encontrada"
+		// (locale-dependent; resolved via the Paraglide message helper).
+		expect(live!.textContent ?? '').toContain(m.person_mention_results_count_singular());
+	});
+
+	it('keeps the visible empty-state copy without its own aria-live and hides it from AT (Leonie #3 on PR #629 round 3; Leonie S-2 round 4)', async () => {
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: 'WdG' } });
+
+		// Visible empty-state <p> exists with the empty-result copy ...
+		const empty = document.querySelector('p.text-ink-3') as HTMLElement | null;
+		expect(empty).not.toBeNull();
+		expect(empty!.textContent ?? '').toContain(m.person_mention_popup_empty());
+		// ... but it must NOT carry its own aria-live (the persistent sr-only
+		// region above the conditional is the announcer now).
+		expect(empty!.hasAttribute('aria-live')).toBe(false);
+		// ... and it MUST be hidden from screen readers via aria-hidden="true"
+		// so VoiceOver does not double-announce (the persistent sr-only region
+		// is the sole AT source of truth). Leonie S-2 on PR #629 round 4.
+		expect(empty!.getAttribute('aria-hidden')).toBe('true');
+	});
+
+	it('renders the magnifier icon at h-5 w-5 with text-ink-2 (Leonie BLOCKER on PR #629)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const icon = document.querySelector('[data-test-search-input]')
+			?.previousElementSibling as SVGElement | null;
+		expect(icon).not.toBeNull();
+		expect(icon!.tagName.toLowerCase()).toBe('svg');
+		expect(icon!.getAttribute('class') ?? '').toContain('h-5');
+		expect(icon!.getAttribute('class') ?? '').toContain('w-5');
+		expect(icon!.getAttribute('class') ?? '').toContain('text-ink-2');
+	});
+
+	it('caps the search input at maxlength=100 (CWE-400 amplification — Nora on PR #629)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLInputElement;
+		expect(input).not.toBeNull();
+		expect(input.maxLength).toBe(100);
+	});
+
+	it('clips a long editorQuery mirror to 100 chars (CWE-400 layered — Nora #1 on PR #629)', async () => {
+		const longQuery = 'A'.repeat(200);
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: longQuery } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLInputElement;
+		expect(input).not.toBeNull();
+		expect(input.value.length).toBe(100);
+		expect(input.value).toBe('A'.repeat(100));
+	});
+
+	it('caps the listbox width to the viewport (320 px reflow guard — Leonie FINDING-MENTION-005)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const listbox = document.querySelector('[role="listbox"]') as HTMLElement;
+		expect(listbox).not.toBeNull();
+		expect(listbox.className).toContain('max-w-[calc(100vw-1rem)]');
+	});
+
+	it('renders the @mention search input at text-base (16 px senior-audience floor — Leonie FINDING-MENTION-006)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLInputElement;
+		expect(input).not.toBeNull();
+		expect(input.className).toContain('text-base');
+		expect(input.className).not.toContain('text-sm');
+	});
+
+	it('invokes onSearch with the current value whenever the user types', async () => {
+		const onSearch = vi.fn();
+		render(MentionDropdown, { props: { model: baseModel(), onSearch } });
+
+		await userEvent.type(page.getByRole('searchbox'), 'Walter');
+
+		await vi.waitFor(() => {
+			expect(onSearch).toHaveBeenCalled();
+			expect(onSearch).toHaveBeenLastCalledWith('Walter');
+		});
+	});
+
+	it('keeps the user-edited search value when editorQuery changes after the takeover (Felix on PR #629)', async () => {
+		let setEditorQuery!: (q: string) => void;
+		render(MentionDropdownFixture, {
+			model: baseModel(),
+			initialEditorQuery: 'WdG',
+			onReady: (s: (q: string) => void) => {
+				setEditorQuery = s;
+			}
+		});
+
+		await expect.element(page.getByRole('searchbox')).toHaveValue('WdG');
+
+		await page.getByRole('searchbox').fill('Walter');
+		await expect.element(page.getByRole('searchbox')).toHaveValue('Walter');
+
+		setEditorQuery('WdGruyter');
+		// Flush pending Svelte reactivity so any (non-)update from the mirror
+		// $effect has landed before we assert. expect.element already polls, so
+		// no fixed-timeout fallback is needed. Sara on PR #629 round 3.
+		await tick();
+
+		await expect.element(page.getByRole('searchbox')).toHaveValue('Walter');
+	});
+});
+
+// ─── ArrowDown via exported onKeyDown (Sara #3 on PR #629) ──────────────────
+//
+// In production, Tiptap intercepts ArrowDown/ArrowUp/Enter at the editor level
+// and forwards them to the dropdown via its exported onKeyDown(event) function
+// — the dropdown itself has no DOM keydown listener. This test exercises the
+// same export so a regression in highlightedIndex/selection logic is caught
+// at the unit level. The full E2E focus-chain test is deferred to a separate
+// issue (Playwright).
+//
+// These unit tests directly invoke the exported `onKeyDown` to pin its
+// behaviour in isolation. They do NOT exercise the Tiptap forwarding
+// chain (PersonMentionEditor.suggestion.render() returning { onKeyDown })
+// — that integration is covered by the 'ArrowDown moves the highlight'
+// test in PersonMentionEditor.svelte.spec.ts. Sara on PR #629 round 3.
+
+describe('MentionDropdown — onKeyDown forwarding', () => {
+	// flushSync ensures Svelte reactivity propagation completes before
+	// asserting (uniform across all four key tests so the next reader
+	// doesn't have to figure out why some are wrapped and others aren't).
+	// Felix #1 suggestion on PR #629 round 3.
+
+	it('ArrowDown advances aria-selected to the next option in the listbox', async () => {
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt'), makePerson('p2', 'Bert Meier')]
+				})
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+
+			// First option starts highlighted.
+			const first = container.querySelector('[data-test-person-id="p1"]') as HTMLElement;
+			const second = container.querySelector('[data-test-person-id="p2"]') as HTMLElement;
+			expect(first.getAttribute('aria-selected')).toBe('true');
+			expect(second.getAttribute('aria-selected')).toBe('false');
+
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'ArrowDown' }));
+			});
+			expect(consumed).toBe(true);
+
+			expect(first.getAttribute('aria-selected')).toBe('false');
+			expect(second.getAttribute('aria-selected')).toBe('true');
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+
+	it('ArrowUp wraps from the first option to the last', async () => {
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt'), makePerson('p2', 'Bert Meier')]
+				})
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'ArrowUp' }));
+			});
+			expect(consumed).toBe(true);
+
+			const second = container.querySelector('[data-test-person-id="p2"]') as HTMLElement;
+			expect(second.getAttribute('aria-selected')).toBe('true');
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+
+	it('Enter invokes model.command with the currently highlighted item', async () => {
+		const command = vi.fn();
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt'), makePerson('p2', 'Bert Meier')],
+					command
+				})
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Enter' }));
+			});
+			expect(consumed).toBe(true);
+			expect(command).toHaveBeenCalledTimes(1);
+			expect(command.mock.calls[0][0].id).toBe('p1');
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+
+	it('Escape returns false so the suggestion plugin can handle it', async () => {
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({ items: [makePerson('p1', 'Anna Schmidt')] })
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+			let consumed = true;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Escape' }));
+			});
+			expect(consumed).toBe(false);
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+});

frontend/src/lib/shared/discussion/MentionDropdown.test-fixture.svelte

@@ -0,0 +1,32 @@
+<script lang="ts">
+import { untrack } from 'svelte';
+import MentionDropdown from './MentionDropdown.svelte';
+import type { components } from '$lib/generated/api';
+
+type Person = components['schemas']['Person'];
+type DropdownState = {
+	items: Person[];
+	command: (item: Person) => void;
+	clientRect: (() => DOMRect | null) | null;
+};
+
+type Props = {
+	model: DropdownState;
+	initialEditorQuery: string;
+	/** Test hook: receives a setter for editorQuery so the test can mutate it. */
+	onReady?: (setEditorQuery: (q: string) => void) => void;
+	onSearch?: (q: string) => void;
+};
+
+let { model, initialEditorQuery, onReady, onSearch = () => {} }: Props = $props();
+
+let editorQuery = $state(untrack(() => initialEditorQuery));
+
+$effect(() => {
+	onReady?.((q) => {
+		editorQuery = q;
+	});
+});
+</script>
+
+<MentionDropdown model={model} editorQuery={editorQuery} onSearch={onSearch} />

frontend/src/lib/shared/discussion/PersonMentionEditor.svelte

@@ -7,7 +7,9 @@ import { m } from '$lib/paraglide/messages.js';
 import type { components } from '$lib/generated/api';
 import type { PersonMention } from '$lib/shared/types';
 import { deserialize, serialize } from '$lib/shared/discussion/mentionSerializer';
+import { debounce } from '$lib/shared/utils/debounce';
 import MentionDropdown from './MentionDropdown.svelte';
+import { MAX_QUERY_LENGTH, SEARCH_DEBOUNCE_MS, SEARCH_RESULT_LIMIT } from './mentionConstants';
 
 type Person = components['schemas']['Person'];
 
@@ -33,6 +35,13 @@ let {
 
 let editorEl: HTMLDivElement;
 let editor: Editor | null = null;
+// Hoisted so onDestroy can guarantee the imperatively-mounted dropdown is
+// torn down even if Tiptap's suggestion plugin onExit didn't fire (e.g. when
+// the host component is unmounted while the dropdown is still open).
+let mountedDropdown: object | null = null;
+// Hoisted so onDestroy can cancel any pending fetch — otherwise a trailing
+// debounced search can fire after the editor is gone and pollute later tests.
+let cancelPendingSearch: (() => void) | null = null;
 
 // Single reactive state object shared with MentionDropdown. Mutating these
 // fields propagates to the mounted dropdown via Svelte's $state proxy —
@@ -42,10 +51,12 @@ let dropdownState = $state<{
 	items: Person[];
 	command: (item: Person) => void;
 	clientRect: (() => DOMRect | null) | null;
+	editorQuery: string;
 }>({
 	items: [],
 	command: () => {},
-	clientRect: null
+	clientRect: null,
+	editorQuery: ''
 });
 
 type DropdownExports = {
@@ -138,16 +149,13 @@ onMount(() => {
 					// Nora #5618 #3 — separate issue tracks the GET /api/persons
 					// response-shape audit (PersonSummaryDTO leaks `notes`).
 					// ─────────────────────────────────────────────────────────────
-					items: async ({ query }: { query: string }) => {
+					// Tiptap's suggestion plugin requires an `items()` callback to keep
-						if (!query) return [];
+					// the dropdown alive, but the actual fetch is owned by `runSearch`
-						try {
+					// below — routed through the dropdown's search input via the
-							const res = await fetch(`/api/persons?q=${encodeURIComponent(query)}`);
+					// debounced `onSearch` channel. Returning `[]` here keeps Tiptap
-							if (!res.ok) return [];
+					// happy without firing a duplicate per-keystroke fetch.
-							return ((await res.json()) as Person[]).slice(0, 5);
+					// Markus #5616 / Felix / Nora / Sara on PR #629.
-						} catch {
+					items: async () => [],
-							return [];
-						}
-					},
 					// AC-1 fix: insert the typed query as displayName, not person.displayName.
 					command({ editor: ed, range, props }) {
 						const p = props as unknown as { personId: string; displayName: string };
@@ -165,7 +173,6 @@ onMount(() => {
 							.run();
 					},
 					render() {
-						let component: object | null = null;
 						let exports: DropdownExports | null = null;
 
 						// Tiptap's SuggestionProps types `command` against the default
@@ -178,25 +185,84 @@ onMount(() => {
 							clientRect?: (() => DOMRect | null) | null;
 						};
 
+						// Request-token guard: every onSearch invocation bumps `requestId`;
+						// runSearch captures the id active when its fetch starts and discards
+						// the response if a newer onSearch has fired since. Without this, a
+						// late response can repopulate the dropdown after the user cleared
+						// the search input. Sara on PR #629.
+						let requestId = 0;
+						const runSearch = async (query: string) => {
+							const id = requestId;
+							try {
+								// Defensive client-side cap — server-side enforcement is tracked
+								// separately. Markus on PR #629.
+								const res = await fetch(
+									`/api/persons?q=${encodeURIComponent(query)}&limit=${SEARCH_RESULT_LIMIT}`
+								);
+								if (id !== requestId) return;
+								if (!res.ok) {
+									dropdownState.items = [];
+									return;
+								}
+								const data = (await res.json()) as Person[];
+								if (id !== requestId) return;
+								dropdownState.items = data.slice(0, SEARCH_RESULT_LIMIT);
+							} catch {
+								if (id !== requestId) return;
+								dropdownState.items = [];
+							}
+						};
+						const debouncedSearch = debounce(runSearch, SEARCH_DEBOUNCE_MS);
+						cancelPendingSearch = () => debouncedSearch.cancel();
+						const onSearch = (query: string) => {
+							requestId++;
+							if (query.trim() === '') {
+								debouncedSearch.cancel();
+								dropdownState.items = [];
+								return;
+							}
+							debouncedSearch(query);
+						};
+
 						const updateState = (renderProps: LooseRenderProps) => {
-							dropdownState.items = renderProps.items as Person[];
+							// Clip once here so both the inserted displayName and the
+							// dropdown's editor-mirror see the same value. The dropdown
+							// already clips the mirror (Nora #1 CWE-400), but without
+							// clipping at the command boundary an unclipped query would
+							// still flow through as the inserted displayName — visible
+							// UI divergence between "what I searched" and "what was
+							// inserted". Felix #3 on PR #629.
+							const clippedQuery = renderProps.query.slice(0, MAX_QUERY_LENGTH);
 							// AC-1: pass typed query as displayName, not person.displayName
 							dropdownState.command = (item: Person) =>
 								renderProps.command({
 									personId: item.id,
-									displayName: renderProps.query
+									displayName: clippedQuery
 								});
 							dropdownState.clientRect = renderProps.clientRect ?? null;
+							dropdownState.editorQuery = clippedQuery;
 						};
 
 						return {
 							onStart(renderProps) {
-								updateState(renderProps as unknown as LooseRenderProps);
+								const loose = renderProps as unknown as LooseRenderProps;
+								updateState(loose);
+								// MentionDropdown reads `editorQuery` off the shared state
+								// proxy via its `editorQuery` prop binding below — this is
+								// the same pattern as `model.items`. We do not pass it as a
+								// separate prop because Svelte 5's mount() does not expose
+								// settable prop accessors, so we route through the proxy.
 								const mounted = mount(MentionDropdown, {
 									target: document.body,
-									props: { model: dropdownState }
+									props: {
+										model: dropdownState,
+										get editorQuery() {
+											return dropdownState.editorQuery;
+										},
+										onSearch
+									}
 								});
-								component = mounted as object;
+								mountedDropdown = mounted as object;
 								exports = mounted as unknown as DropdownExports;
 							},
 							onUpdate(renderProps) {
@@ -208,9 +274,16 @@ onMount(() => {
 								return exports?.onKeyDown(event) ?? false;
 							},
 							onExit() {
-								if (component) {
+								// Cancel any pending debounce so a closed dropdown's trailing
-									unmount(component);
+								// runSearch cannot fire against the *next* dropdown's state.
-									component = null;
+								// The hoisted `cancelPendingSearch` would be overwritten by
+								// the next render()'s onStart before the trailing call fires,
+								// so we cancel locally via the closure-scoped debouncedSearch.
+								// Felix #1 on PR #629.
+								debouncedSearch.cancel();
+								if (mountedDropdown) {
+									unmount(mountedDropdown);
+									mountedDropdown = null;
 									exports = null;
 								}
 							}
@@ -253,7 +326,15 @@ onMount(() => {
 });
 
 onDestroy(() => {
+	cancelPendingSearch?.();
 	editor?.destroy();
+	// Tiptap suggestion onExit usually unmounts the dropdown, but if the host
+	// component is destroyed while a suggestion is active the dropdown can
+	// outlive the editor — clean it up explicitly.
+	if (mountedDropdown) {
+		unmount(mountedDropdown);
+		mountedDropdown = null;
+	}
 });
 
 // Keep the data-placeholder attribute in sync with actual emptiness so the

frontend/src/lib/shared/discussion/PersonMentionEditor.svelte.spec.ts

@@ -8,29 +8,45 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
-import PersonMentionEditorHost from './PersonMentionEditor.test-host.svelte';
+import { tick } from 'svelte';
+import PersonMentionEditorHost from './PersonMentionEditor.test-fixture.svelte';
 import type { components } from '$lib/generated/api';
 import { m } from '$lib/paraglide/messages.js';
+// Single source of truth for the debounce window — imported from the shared
+// module so the test cannot drift from production. Sara on PR #629 round 3.
+import { SEARCH_DEBOUNCE_MS } from './mentionConstants';
 
 type Person = components['schemas']['Person'];
 type PersonMention = components['schemas']['PersonMention'];
 
+/**
+ * Headroom above SEARCH_DEBOUNCE_MS for the debounce-window wait
+ * assertions in this file. 350 ms is calibrated against CI-runner jitter
+ * we observed pre-#629; dropping it below ~200 ms reintroduces flake.
+ * See PR #629 round-2 review comment #10935 (Sara).
+ */
+const POST_DEBOUNCE_SLACK_MS = 350;
+
 const AUGUSTE: Person = {
 	id: 'p-aug',
 	firstName: 'Auguste',
 	lastName: 'Raddatz',
 	displayName: 'Auguste Raddatz',
+	personType: 'PERSON',
+	familyMember: false,
 	birthYear: 1882,
 	deathYear: 1944
-} as unknown as Person;
+};
 
 const ANNA: Person = {
 	id: 'p-anna',
 	firstName: 'Anna',
 	lastName: 'Schmidt',
 	displayName: 'Anna Schmidt',
+	personType: 'PERSON',
+	familyMember: false,
 	birthYear: 1860
-} as unknown as Person;
+};
 
 function mockFetchWithPersons(persons: Person[] = [AUGUSTE, ANNA]) {
 	vi.stubGlobal(
@@ -125,6 +141,20 @@ describe('PersonMentionEditor — typeahead', () => {
 		});
 	});
 
+	it('appends &limit=5 to the fetch URL (defensive client-side cap, Markus on PR #629)', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+
+		await vi.waitFor(() => {
+			expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('limit=5'));
+		});
+	});
+
 	it('shows life dates next to the name in the dropdown', async () => {
 		mockFetchWithPersons();
 		renderHost();
@@ -142,8 +172,15 @@ describe('PersonMentionEditor — typeahead', () => {
 
 		await userEvent.type(page.getByRole('textbox'), '@xyz');
 
-		await vi.waitFor(async () => {
+		// The visible empty-state <p> (text-ink-3) shows the copy. The persistent
-			await expect.element(page.getByText('Keine Personen gefunden')).toBeInTheDocument();
+		// sr-only aria-live region also contains the same copy, so we scope to the
+		// visible element to avoid a multi-match resolution in expect.element.
+		await vi.waitFor(() => {
+			const visibleEmptyP = document.querySelector(
+				'[role="listbox"] p.text-ink-3'
+			) as HTMLElement | null;
+			expect(visibleEmptyP).not.toBeNull();
+			expect(visibleEmptyP!.textContent ?? '').toContain('Keine Personen gefunden');
 		});
 	});
 
@@ -161,6 +198,254 @@ describe('PersonMentionEditor — typeahead', () => {
 	});
 });
 
+// ─── AC-2/3: search input drives the person fetch (debounced) ───────────────
+
+describe('PersonMentionEditor — AC-2/3: search input drives fetch', () => {
+	it('editing the search input fires a debounced fetch with the new query', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown so the search input is reachable.
+		await userEvent.type(page.getByRole('textbox'), '@');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+
+		const fetchesBeforeSearch = fetchMock.mock.calls.length;
+
+		// `fill` simulates a single input event with the final value — sidesteps
+		// per-keystroke timing of userEvent.type so the test can deterministically
+		// assert that one input event collapses into one debounced fetch.
+		await page.getByRole('searchbox').fill('Walter');
+
+		await vi.waitFor(
+			() => {
+				expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('q=Walter'));
+			},
+			{ timeout: 1000 }
+		);
+
+		const fetchesAfterSearch = fetchMock.mock.calls.length - fetchesBeforeSearch;
+		expect(fetchesAfterSearch).toBe(1);
+	});
+
+	it('fires exactly one /api/persons fetch when the user searches for Walter (regression guard)', async () => {
+		// Regression guard: a previous version of PersonMentionEditor had a
+		// duplicated `items()` callback in the Tiptap suggestion config that
+		// fetched per-keystroke in addition to the debounced search-input fetch
+		// (Markus & Felix round-1). To catch that regression, we must NOT
+		// subtract any baseline — every fetch from render onwards counts.
+		// Sara on PR #629 round 3.
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown, then drive the search input via fill() — sidesteps
+		// per-keystroke timing of userEvent.type that Sara flagged round 2.
+		await userEvent.type(page.getByRole('textbox'), '@');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+		await page.getByRole('searchbox').fill('Walter');
+
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		// No baseline subtraction — count ALL /api/persons fetches since render.
+		// If the legacy per-keystroke items() callback returns, typing `@` alone
+		// would already produce one fetch and `fill('Walter')` another, breaking
+		// this assertion.
+		const personsFetches = fetchMock.mock.calls.filter(
+			([url]) => typeof url === 'string' && url.startsWith('/api/persons')
+		);
+		expect(personsFetches.length).toBe(1);
+	});
+
+	it('clearing the search input clears the list without firing a fetch', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByText('Auguste Raddatz')).toBeInTheDocument();
+		});
+
+		const fetchesBeforeClear = fetchMock.mock.calls.length;
+
+		await userEvent.clear(page.getByRole('searchbox'));
+
+		// Negative assertion: wait past the debounce window to confirm no
+		// trailing fetch was scheduled. Removing this wait would mask a
+		// re-introduction of the keystroke-driven items() fetch.
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		expect(fetchMock.mock.calls.length).toBe(fetchesBeforeClear);
+		await expect.element(page.getByText('Auguste Raddatz')).not.toBeInTheDocument();
+	});
+});
+
+// ─── Whitespace-only query (Elicit AC-4 ambiguity on PR #629) ───────────────
+
+describe('PersonMentionEditor — whitespace-only query', () => {
+	it('keeps the "Namen eingeben…" prompt and fires no fetch when @ is followed only by spaces', async () => {
+		const fetchMock = vi.fn().mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@   ');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		// Scope to the visible empty-state <p> (text-ink-3) — the persistent
+		// sr-only aria-live region above contains the same copy.
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_search_prompt());
+		expect(fetchMock).not.toHaveBeenCalled();
+	});
+});
+
+// ─── Stale-response race (Sara on PR #629) ───────────────────────────────────
+
+describe('PersonMentionEditor — stale-response race', () => {
+	it('discards a stale response that resolves after the search has been cleared', async () => {
+		let resolveFetch!: (v: { ok: boolean; json: () => Promise<Person[]> }) => void;
+		const pendingResponse = new Promise<{ ok: boolean; json: () => Promise<Person[]> }>((r) => {
+			resolveFetch = r;
+		});
+		const fetchMock = vi.fn().mockReturnValue(pendingResponse);
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown and let the debounce fire so a fetch is in flight.
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await vi.waitFor(() => {
+			expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('/api/persons?q=Aug'));
+		});
+
+		// Clear the search input *before* the fetch resolves.
+		await userEvent.clear(page.getByRole('searchbox'));
+		await expect.element(page.getByRole('searchbox')).toHaveValue('');
+
+		// The stale fetch now resolves with persons. The dropdown must stay empty.
+		resolveFetch({ ok: true, json: () => Promise.resolve([AUGUSTE]) });
+		// Flush pending Svelte reactivity so any (non-)update from the stale
+		// fetch resolution has landed before we assert. expect.element already
+		// polls, so no fixed-timeout fallback is needed. Sara on PR #629 round 4.
+		await tick();
+
+		await expect.element(page.getByText('Auguste Raddatz')).not.toBeInTheDocument();
+	});
+});
+
+// ─── Server failure characterization (Sara #2 on PR #629) ───────────────────
+
+describe('PersonMentionEditor — server failure', () => {
+	it('on 500 response keeps the dropdown open with the empty-state copy (silent failure pinned; distinct error UX tracked separately)', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: false, status: 500, json: vi.fn().mockResolvedValue({}) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		// Pins current silent-failure behaviour. The day someone implements a
+		// distinct error UX (toast / "Suche fehlgeschlagen" copy), this test
+		// goes red and forces them to update the assertion. Scope to the
+		// visible <p> (text-ink-3) — the persistent sr-only live region
+		// above contains the same copy.
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_popup_empty());
+	});
+
+	it('on a fetch reject (network failure) keeps the dropdown open with the empty-state copy', async () => {
+		const fetchMock = vi.fn().mockRejectedValue(new TypeError('NetworkError'));
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_popup_empty());
+	});
+});
+
+// ─── onExit cancels pending debounce (Felix #1 on PR #629) ───────────────────
+
+describe('PersonMentionEditor — onExit cancels pending debounce', () => {
+	it('cancels the pending debounced fetch when Escape closes the dropdown before the debounce fires', async () => {
+		const fetchMock = vi.fn().mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown by typing @ + a query in the editor.
+		await userEvent.type(page.getByRole('textbox'), '@A');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+
+		// Wait for any in-flight fetch from opening the dropdown to settle.
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+		const fetchesBeforeEscape = fetchMock.mock.calls.length;
+
+		// Trigger a new debounced search (queues runSearch after 150 ms), then
+		// immediately Escape *while focus is back in the editor* so Tiptap's
+		// suggestion-plugin Escape handler fires onExit before the debounce.
+		// Without onExit cancelling the pending debounce, runSearch executes
+		// against the now-unmounted dropdown's state.
+		await page.getByRole('searchbox').fill('Walter');
+		// Focus the editor so the Escape lands on Tiptap's suggestion handler.
+		(page.getByRole('textbox').element() as HTMLElement).focus();
+		await userEvent.keyboard('{Escape}');
+
+		// Wait past the debounce window. If onExit did not cancel the pending
+		// debounce, a fetch with q=Walter would still fire here.
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		const newFetches = fetchMock.mock.calls.slice(fetchesBeforeEscape);
+		const walterFetches = newFetches.filter(
+			([url]) => typeof url === 'string' && url.includes('q=Walter')
+		);
+		expect(walterFetches.length).toBe(0);
+	});
+});
+
+// ─── AC-1: search input prefilled with text typed after @ ───────────────────
+
+describe('PersonMentionEditor — AC-1: search input prefill', () => {
+	it('prefills the dropdown search input with the text typed after @', async () => {
+		mockFetchEmpty();
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@WdG');
+
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toHaveValue('WdG');
+		});
+	});
+});
+
 // ─── AC-1: typed text becomes displayName, not DB name ───────────────────────
 
 describe('PersonMentionEditor — AC-1: typed text as displayName', () => {
@@ -229,6 +514,39 @@ describe('PersonMentionEditor — AC-1: typed text as displayName', () => {
 		});
 	});
 
+	it('clips the inserted displayName to MAX_QUERY_LENGTH=100 chars (Felix #3 on PR #629)', async () => {
+		// CWE-400 amplification: the dropdown clips its search input + mirror at
+		// 100 chars (Nora #1), but the host editor was passing the unclipped
+		// renderProps.query straight through to displayName — so a 105-char
+		// @-suffix in the editor could insert a 105-char displayName into the
+		// sidecar even though the dropdown only searched the first 100.
+		mockFetchWithPersons();
+		const host = renderHost();
+
+		// Type @ + 105 'A' chars in the contenteditable. The renderProps.query
+		// fed into the command callback derives from the editor text after `@`,
+		// not the dropdown's searchbox — so we must drive the editor.
+		await userEvent.type(page.getByRole('textbox'), '@' + 'A'.repeat(105));
+
+		// The mocked /api/persons returns AUGUSTE for any query — wait for it.
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('option', { name: /Auguste Raddatz/ })).toBeVisible();
+		});
+
+		const option = (await page
+			.getByRole('option', { name: /Auguste Raddatz/ })
+			.element()) as HTMLElement;
+		option.dispatchEvent(new MouseEvent('mousedown', { bubbles: true, cancelable: true }));
+
+		await vi.waitFor(() => {
+			expect(host.snapshot.mentionedPersons).toHaveLength(1);
+			// Tight assertion: input is 105 chars, cap is exactly 100. Using
+			// `toHaveLength(100)` discriminates "clip works" from "clip works
+			// AND nothing weakened it to e.g. 95". Sara on PR #629 round 4.
+			expect(host.snapshot.mentionedPersons[0].displayName).toHaveLength(100);
+		});
+	});
+
 	it('does not duplicate the sidecar entry when the same person is selected twice', async () => {
 		mockFetchWithPersons();
 		const host = renderHost({

frontend/src/lib/shared/discussion/mentionConstants.ts

@@ -0,0 +1,10 @@
+/** Shared knobs for the @mention typeahead. Single source of truth for
+ *  the dropdown component and the host editor — keeps the layered length
+ *  cap and the debounce window consistent across both files. */
+export const MAX_QUERY_LENGTH = 100;
+export const SEARCH_DEBOUNCE_MS = 150;
+/** Defensive client-side cap on the result list. Single consumer today
+ *  (PersonMentionEditor), kept here for symmetry with the other limit
+ *  knobs so the @mention configuration lives in one place. Felix #1 on
+ *  PR #629 round 4. */
+export const SEARCH_RESULT_LIMIT = 5;

frontend/src/lib/shared/services/confirm.svelte.test.ts

@@ -1,7 +1,7 @@
 import { describe, it, expect, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
-import TestHost from './confirm.test-host.svelte';
+import TestHost from './confirm.test-fixture.svelte';
 import type { ConfirmService } from './confirm.svelte.js';
 
 afterEach(cleanup);

frontend/src/lib/shared/utils/debounce.ts

@@ -1,12 +1,25 @@
 /**
  * Returns a debounced version of fn that delays invocation until after
- * `delay` ms have elapsed since the last call.
+ * `delay` ms have elapsed since the last call. The returned function
+ * exposes a `cancel()` method that DROPS (does not flush) the pending
+ * trailing invocation — essential when the host context (a destroyed
+ * component, an unmounted editor) shouldn't fire the trailing call.
  */
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function debounce<T extends (...args: any[]) => void>(fn: T, delay: number): T {
+export function debounce<T extends (...args: any[]) => void>(
-	let timer: ReturnType<typeof setTimeout>;
+	fn: T,
-	return ((...args: Parameters<T>) => {
+	delay: number
-		clearTimeout(timer);
+): T & { cancel: () => void } {
+	let timer: ReturnType<typeof setTimeout> | undefined;
+	const wrapped = ((...args: Parameters<T>) => {
+		if (timer !== undefined) clearTimeout(timer);
 		timer = setTimeout(() => fn(...args), delay);
-	}) as T;
+	}) as T & { cancel: () => void };
+	wrapped.cancel = () => {
+		if (timer !== undefined) {
+			clearTimeout(timer);
+			timer = undefined;
+		}
+	};
+	return wrapped;
 }

frontend/src/routes/aktivitaeten/+page.server.ts

@@ -1,4 +1,6 @@
+import { fail } from '@sveltejs/kit';
 import { createApiClient } from '$lib/shared/api.server';
+import { getErrorMessage } from '$lib/shared/errors';
 import type { components, operations } from '$lib/generated/api';
 
 type ActivityFeedItemDTO = components['schemas']['ActivityFeedItemDTO'];
@@ -65,3 +67,31 @@ export async function load({ fetch, url }) {
 		loadError
 	};
 }
+
+export const actions = {
+	'dismiss-notification': async ({ request, fetch }) => {
+		const data = await request.formData();
+		const raw = data.get('notificationId');
+		const notificationId = typeof raw === 'string' ? raw : null;
+		if (!notificationId) return fail(400, { error: getErrorMessage(undefined) });
+		const api = createApiClient(fetch);
+		const result = await api.PATCH('/api/notifications/{id}/read', {
+			params: { path: { id: notificationId } }
+		});
+		if (!result.response.ok) {
+			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, { error: getErrorMessage(code) });
+		}
+		return { success: true };
+	},
+
+	'mark-all-read': async ({ fetch }) => {
+		const api = createApiClient(fetch);
+		const result = await api.POST('/api/notifications/read-all');
+		if (!result.response.ok) {
+			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, { error: getErrorMessage(code) });
+		}
+		return { success: true };
+	}
+};

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

@@ -76,14 +76,6 @@ async function onFilterChange(v: FilterValue) {
 	});
 }
 
-async function onMarkRead(n: NotificationItem) {
-	await notificationStore.markRead(n);
-}
-
-async function onMarkAllRead() {
-	await notificationStore.markAllRead();
-}
-
 const displayFeed = $derived(applyClientFilter(data.activityFeed, data.filter));
 
 const isEmpty = $derived(displayFeed.length === 0);
@@ -108,7 +100,11 @@ function retry() {
 	{#if data.loadError === 'activity'}
 		<ChronikErrorCard onRetry={retry} />
 	{:else}
-		<ChronikFuerDichBox unread={unread} onMarkRead={onMarkRead} onMarkAllRead={onMarkAllRead} />
+		<ChronikFuerDichBox
+			unread={unread}
+			optimisticMarkRead={notificationStore.optimisticMarkRead}
+			optimisticMarkAllRead={notificationStore.optimisticMarkAllRead}
+		/>
 
 		<div class="mt-6">
 			<ChronikFilterPills value={data.filter} onChange={onFilterChange} />

frontend/src/routes/aktivitaeten/page.server.spec.ts

@@ -1,8 +1,10 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest';
-import { load } from './+page.server';
+import { load, actions } from './+page.server';
 
 const mockApi = {
-	GET: vi.fn()
+	GET: vi.fn(),
+	PATCH: vi.fn(),
+	POST: vi.fn()
 };
 
 vi.mock('$lib/shared/api.server', () => ({
@@ -173,3 +175,84 @@ describe('aktivitaeten/load — kinds param per filter', () => {
 		expect(call[1].params.query.kinds).toHaveLength(2);
 	});
 });
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+function makeActionEvent(formData: FormData): any {
+	return {
+		request: new Request('http://localhost/aktivitaeten', { method: 'POST', body: formData }),
+		fetch
+	};
+}
+
+describe('aktivitaeten/actions — dismiss-notification', () => {
+	it('returns fail(400, { error }) and does NOT call PATCH when notificationId is missing', async () => {
+		const result = await actions['dismiss-notification'](makeActionEvent(new FormData()));
+
+		expect(result).toMatchObject({ status: 400 });
+		expect(mockApi.PATCH).not.toHaveBeenCalled();
+	});
+
+	it('calls PATCH /api/notifications/{id}/read with the form-supplied notificationId', async () => {
+		mockApi.PATCH.mockResolvedValue({ response: { ok: true }, data: {} });
+		const fd = new FormData();
+		fd.set('notificationId', 'n-abc');
+
+		await actions['dismiss-notification'](makeActionEvent(fd));
+
+		expect(mockApi.PATCH).toHaveBeenCalledWith('/api/notifications/{id}/read', {
+			params: { path: { id: 'n-abc' } }
+		});
+	});
+
+	it('returns { success: true } when the API responds ok', async () => {
+		mockApi.PATCH.mockResolvedValue({ response: { ok: true }, data: {} });
+		const fd = new FormData();
+		fd.set('notificationId', 'n-abc');
+
+		const result = await actions['dismiss-notification'](makeActionEvent(fd));
+
+		expect(result).toEqual({ success: true });
+	});
+
+	it('returns fail(status, { error }) when the API responds non-ok', async () => {
+		mockApi.PATCH.mockResolvedValue({
+			response: { ok: false, status: 403 },
+			error: { code: 'NOTIFICATION_NOT_FOUND' }
+		});
+		const fd = new FormData();
+		fd.set('notificationId', 'n-abc');
+
+		const result = await actions['dismiss-notification'](makeActionEvent(fd));
+
+		expect(result).toMatchObject({ status: 403 });
+	});
+});
+
+describe('aktivitaeten/actions — mark-all-read', () => {
+	it('calls POST /api/notifications/read-all', async () => {
+		mockApi.POST.mockResolvedValue({ response: { ok: true }, data: null });
+
+		await actions['mark-all-read'](makeActionEvent(new FormData()));
+
+		expect(mockApi.POST).toHaveBeenCalledWith('/api/notifications/read-all');
+	});
+
+	it('returns { success: true } when the API responds ok', async () => {
+		mockApi.POST.mockResolvedValue({ response: { ok: true }, data: null });
+
+		const result = await actions['mark-all-read'](makeActionEvent(new FormData()));
+
+		expect(result).toEqual({ success: true });
+	});
+
+	it('returns fail(status, { error }) when the API responds non-ok', async () => {
+		mockApi.POST.mockResolvedValue({
+			response: { ok: false, status: 500 },
+			error: { code: 'INTERNAL_ERROR' }
+		});
+
+		const result = await actions['mark-all-read'](makeActionEvent(new FormData()));
+
+		expect(result).toMatchObject({ status: 500 });
+	});
+});

infra/observability/grafana/provisioning/dashboards/loki-logs.json

@@ -196,7 +196,7 @@
       },
       "targets": [
         {
-          "expr": "{job=\"$app\"} |= \"$search\" | logfmt",
+          "expr": "{job=\"$app\"} |= \"$search\" | json",
           "hide": false,
           "legendFormat": "",
           "refId": "A"