feat(dashboard): add reader dashboard components

Adds 5 new components for the permission-gated reader layout:
- ReaderStatsStrip: stat tiles (documents / persons / stories) linking to list pages
- ReaderPersonChips: top-N persons by doc count with avatar + name
- ReaderDraftsModule: blog draft list for BLOG_WRITE users
- ReaderRecentDocs: 5 most-recently-updated docs with Neu/Aktualisiert badge
- ReaderRecentStories: 3 latest published stories with 150-char HTML-stripped excerpt

Each component ships with a vitest-browser spec covering the key assertions.
Avatar color/initials logic is inlined to satisfy $lib/shared → $lib/person
boundary rule.

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

frontend/src/lib/shared/dashboard/ReaderRecentStories.svelte

@@ -0,0 +1,53 @@
+<script lang="ts">
+import * as m from '$lib/paraglide/messages.js';
+import { relativeTimeDe } from '$lib/shared/relativeTime';
+import type { components } from '$lib/generated/api';
+
+type Geschichte = components['schemas']['Geschichte'];
+
+interface Props {
+	stories: Geschichte[];
+}
+
+const { stories }: Props = $props();
+
+function stripHtml(html: string): string {
+	return html.replace(/<[^>]*>/g, '');
+}
+
+function excerpt(body: string | undefined): string {
+	if (!body) return '';
+	const text = stripHtml(body);
+	if (text.length <= 150) return text;
+	return text.slice(0, 150) + '…';
+}
+</script>
+
+{#if stories.length > 0}
+	<div class="rounded-sm border border-line bg-surface p-6 shadow-sm">
+		<h2 class="mb-5 text-xs font-bold tracking-widest text-ink-3 uppercase">
+			{m.dashboard_reader_recent_stories_heading()}
+		</h2>
+		<ul class="flex flex-col divide-y divide-line">
+			{#each stories as story (story.id)}
+				<li class="py-4 first:pt-0 last:pb-0">
+					<a
+						href="/geschichten/{story.id}"
+						class="flex flex-col gap-1 rounded-sm transition-colors hover:text-brand-mint focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:outline-none"
+					>
+						<span class="text-ink-1 font-serif text-base italic">{story.title}</span>
+						{#if story.body}
+							<p class="line-clamp-2 font-sans text-xs text-ink-3">{excerpt(story.body)}</p>
+						{/if}
+						<span class="font-sans text-xs text-ink-3">
+							{relativeTimeDe(new Date(story.publishedAt ?? story.updatedAt))}
+						</span>
+					</a>
+				</li>
+			{/each}
+		</ul>
+		<a href="/geschichten" class="mt-4 block font-sans text-sm text-brand-mint hover:underline">
+			{m.dashboard_reader_all_stories()}
+		</a>
+	</div>
+{/if}