fix(dashboard): retarget feed footer to /chronik + render rollup rows

- "Alle anzeigen" link now goes to /chronik (was /documents — the dead-end
  bug called out in #285).
- Rollup rows (count > 1) render a primary-colored count badge plus a
  compound timestamp line: "14. Apr. · 14:02–14:32" (en-dash U+2013).
- Singleton rows render the existing "14. Apr. 2026" date line.
- BLOCK_REVIEWED now has a verb mapping (re-using the annotation verb until
  the spec pins a distinct copy).
- Three new spec cases: rollup count badge + en-dash range, no badge on
  singletons, /chronik link assertion.

Part of #285.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/DashboardActivityFeed.svelte

@@ -1,6 +1,8 @@
 <script lang="ts">
 import * as m from '$lib/paraglide/messages.js';
-import type { ActivityFeedItemDTO } from '$lib/generated/api';
+import type { components } from '$lib/generated/api';
+
+type ActivityFeedItemDTO = components['schemas']['ActivityFeedItemDTO'];
 
 interface Props {
 	feed: ActivityFeedItemDTO[];
@@ -12,6 +14,7 @@ const verbMap: Record<string, string> = {
 	TEXT_SAVED: m.audit_action_text_saved(),
 	FILE_UPLOADED: m.audit_action_file_uploaded(),
 	ANNOTATION_CREATED: m.audit_action_annotation_created(),
+	BLOCK_REVIEWED: m.audit_action_annotation_created(),
 	COMMENT_ADDED: m.audit_action_comment_added(),
 	MENTION_CREATED: m.audit_action_mention_created()
 };
@@ -27,6 +30,24 @@ function formatDate(iso: string): string {
 		year: 'numeric'
 	}).format(new Date(iso));
 }
+
+function formatTime(iso: string): string {
+	return new Intl.DateTimeFormat('de-DE', { hour: '2-digit', minute: '2-digit' }).format(
+		new Date(iso)
+	);
+}
+
+// Rollup rows get "14. Apr. · 14:02–14:32"; singletons stay "14. Apr. 2026".
+function timestamp(item: ActivityFeedItemDTO): string {
+	if (item.happenedAtUntil && item.count > 1) {
+		const short = new Intl.DateTimeFormat('de-DE', {
+			day: 'numeric',
+			month: 'short'
+		}).format(new Date(item.happenedAt));
+		return `${short} \u00b7 ${formatTime(item.happenedAt)}\u2013${formatTime(item.happenedAtUntil)}`;
+	}
+	return formatDate(item.happenedAt);
+}
 </script>
 
 <section class="rounded-sm border border-line bg-surface p-5">
@@ -35,7 +56,7 @@ function formatDate(iso: string): string {
 			{m.feed_caption()}
 		</h2>
 		<a
-			href="/documents"
+			href="/chronik"
 			aria-label={m.feed_show_all()}
 			class="font-sans text-xs text-ink-3 transition-colors hover:text-ink">{m.feed_show_all()}</a
 		>
@@ -66,6 +87,14 @@ function formatDate(iso: string): string {
 							<a href="/documents/{item.documentId}" class="underline hover:text-ink">
 								{item.documentTitle}
 							</a>
+							{#if item.count > 1}
+								<span
+									data-testid="feed-rollup-count"
+									class="ml-1.5 inline-block rounded-sm bg-primary px-2 py-0.5 font-sans text-[10px] font-bold text-primary-fg"
+								>
+									{item.count}
+								</span>
+							{/if}
 							{#if item.youMentioned}
 								<span
 									class="ml-1.5 inline-block rounded-full border border-accent px-2 py-px font-sans text-[10px] font-bold text-accent"
@@ -74,7 +103,7 @@ function formatDate(iso: string): string {
 								</span>
 							{/if}
 						</p>
-						<p class="mt-0.5 font-sans text-xs text-ink-3">{formatDate(item.happenedAt)}</p>
+						<p class="mt-0.5 font-sans text-xs text-ink-3">{timestamp(item)}</p>
 					</div>
 				</li>
 			{/each}

frontend/src/lib/components/DashboardActivityFeed.svelte.spec.ts

@@ -17,7 +17,8 @@ const baseItem: ActivityFeedItemDTO = {
 	documentId: 'doc-1',
 	documentTitle: 'Brief 1920',
 	happenedAt: '2026-04-19T10:00:00Z',
-	youMentioned: false
+	youMentioned: false,
+	count: 1
 };
 
 describe('DashboardActivityFeed', () => {
@@ -39,4 +40,30 @@ describe('DashboardActivityFeed', () => {
 		const section = page.getByText('Kommentare & Aktivität');
 		await expect.element(section).toBeInTheDocument();
 	});
+
+	it('renders count badge and en-dash time range for rollup rows (count > 1)', async () => {
+		const rollup: ActivityFeedItemDTO = {
+			...baseItem,
+			count: 20,
+			happenedAtUntil: '2026-04-19T10:32:00Z'
+		};
+		render(DashboardActivityFeed, { feed: [rollup] });
+		const badge = page.getByTestId('feed-rollup-count');
+		await expect.element(badge).toHaveTextContent('20');
+		// "–" is U+2013 en-dash
+		const stamp = page.getByText(/\u2013/);
+		await expect.element(stamp).toBeInTheDocument();
+	});
+
+	it('does not render count badge for singleton rows (count === 1)', async () => {
+		render(DashboardActivityFeed, { feed: [baseItem] });
+		const badge = page.getByTestId('feed-rollup-count');
+		await expect.element(badge).not.toBeInTheDocument();
+	});
+
+	it('links the "show all" footer to /chronik, not /documents', async () => {
+		render(DashboardActivityFeed, { feed: [] });
+		const link = page.getByRole('link', { name: /alle anzeigen/i });
+		await expect.element(link).toHaveAttribute('href', '/chronik');
+	});
 });