feat(#240): Mission Control Strip frontend — 5 components + dashboard wiring

Adds the full-width 3-column collaboration widget below the existing
dashboard grid. Renders without the backend running (Promise.allSettled
isolation keeps failures silent).

Components (src/lib/components/):
- ExpertBadge.svelte — purple pill with icon, no props
- SegmentationColumn.svelte — col 1: links to /enrich/{id}, weekly pulse
- TranscriptionColumn.svelte — col 2: per-doc progress bar when blocks exist
- ReadyColumn.svelte — col 3: mint border when filled, dashed empty state
- MissionControlStrip.svelte — strip wrapper, 1-col mobile / 3-col sm+

i18n: 19 new keys added to de/en/es (mission_control_*)

Page wiring:
- +page.server.ts: 4 new Promise.allSettled calls for segmentation-queue,
  transcription-queue, ready-to-read, weekly-stats; all failures silent
- +page.svelte: MissionControlStrip rendered below the grid in isDashboard

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

frontend/src/lib/components/SegmentationColumn.svelte

@@ -0,0 +1,71 @@
+<script lang="ts">
+import * as m from '$lib/paraglide/messages.js';
+import { getLocale } from '$lib/paraglide/runtime.js';
+import ExpertBadge from './ExpertBadge.svelte';
+
+type TranscriptionQueueItemDTO = {
+	id: string;
+	title: string;
+	documentDate?: string;
+	needsExpert: boolean;
+	annotationCount: number;
+	textedBlockCount: number;
+	reviewedBlockCount: number;
+};
+
+interface Props {
+	docs: TranscriptionQueueItemDTO[];
+	weeklyCount: number;
+}
+
+let { docs, weeklyCount }: Props = $props();
+
+function formatDate(dateStr: string): string {
+	return new Intl.DateTimeFormat(getLocale(), {
+		day: 'numeric',
+		month: 'short',
+		year: 'numeric'
+	}).format(new Date(dateStr + 'T12:00:00'));
+}
+</script>
+
+<div>
+	<div class="mb-1 flex items-center gap-2">
+		<h3 class="font-sans text-xs font-bold tracking-widest text-gray-400 uppercase">
+			{m.mission_control_segmentation_heading()}
+		</h3>
+		{#if weeklyCount > 0}
+			<span class="rounded-full bg-green-50 px-2 py-0.5 text-xs font-semibold text-green-700">
+				{m.mission_control_weekly_pulse({ count: weeklyCount })}
+			</span>
+		{/if}
+	</div>
+	<p class="mt-1 mb-3 text-xs text-gray-400">
+		{m.mission_control_segmentation_description()}
+	</p>
+
+	{#if docs.length === 0}
+		<p class="text-xs text-gray-400 italic">{m.mission_control_segmentation_empty()}</p>
+	{:else}
+		<ul class="space-y-1">
+			{#each docs as doc (doc.id)}
+				<li>
+					<a
+						href="/enrich/{doc.id}"
+						class="hover:bg-brand-sand/30 flex min-h-[44px] flex-col justify-center rounded px-1 py-2 focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:ring-offset-2 focus-visible:outline-none"
+					>
+						<div class="flex flex-wrap items-center gap-1.5">
+							<span class="font-serif text-sm text-ink">{doc.title}</span>
+							{#if doc.needsExpert}
+								<ExpertBadge />
+							{/if}
+						</div>
+						{#if doc.documentDate}
+							<span class="mt-0.5 text-xs text-gray-400">{formatDate(doc.documentDate)}</span>
+						{/if}
+					</a>
+				</li>
+			{/each}
+		</ul>
+	{/if}
+</div>