fix(#240): align Mission Control Strip UI with final spec

- Strip heading: "Mitarbeiten" → "Was braucht Aufmerksamkeit?"
- Column 1 heading: "Segmentierung" → "Rahmen einzeichnen"; add green
  skill pill "✓ Ohne Vorkenntnisse"; heading color gray → ink (navy)
- Column 2 heading: "Transkription" → "Text eintippen"; add navy skill
  pill "Kurrent hilfreich"; heading color gray → ink; weekly pulse
  color green → ink (task, not achievement); progress bar track
  bg-gray-200/h-1.5 → bg-ink/20/h-1; add transition-all to fill
- Column 3 heading: "Lesefertig" → "Lesefertig ✓"; heading color
  gray → green-800; add "N Dokumente bereit" subtitle in green; add
  "Alle N lesen →" link at bottom; reviewed % color gray → green-800
- All columns: add CTA buttons at bottom (Jetzt einzeichnen /
  Jetzt tippen); empty state removed from cols 1 & 2 (columns
  hide when empty); empty-state ghost CTA in col 3 restyled as
  bordered button with hover:bg-ink
- Strip: add visibility guard — hides when all three lists are empty
- i18n: add mission_control_seg_skill_pill, mission_control_trans_skill_pill,
  mission_control_ready_subtitle, mission_control_ready_all_cta in
  de/en/es; update heading and CTA copy in all three locales

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

frontend/src/lib/components/SegmentationColumn.svelte

@@ -29,24 +29,23 @@ function formatDate(dateStr: string): string {
 }
 </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 })}
+{#if docs.length > 0}
+	<div class="flex flex-col gap-3 rounded-sm border border-line bg-surface p-4">
+		<div>
+			<h3 class="mb-1 font-sans text-xs font-bold tracking-widest text-ink uppercase">
+				{m.mission_control_segmentation_heading()}
+			</h3>
+			<span
+				class="inline-flex items-center gap-1 rounded-full border border-green-200 bg-green-50 px-2 py-0.5 text-xs font-semibold text-green-800"
+			>
+				{m.mission_control_seg_skill_pill()}
 			</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}
+			{#if weeklyCount > 0}
+				<p class="mt-1 text-xs font-semibold text-green-700">
+					{m.mission_control_weekly_pulse({ count: weeklyCount })}
+				</p>
+			{/if}
+		</div>
 		<ul class="space-y-1">
 			{#each docs as doc (doc.id)}
 				<li>
@@ -67,5 +66,11 @@ function formatDate(dateStr: string): string {
 				</li>
 			{/each}
 		</ul>
-	{/if}
-</div>
+		<a
+			href="/enrich?filter=NEEDS_SEGMENTATION&next=1"
+			class="mt-auto block w-full rounded-sm bg-ink py-2 text-center text-xs font-semibold text-white transition-colors hover:bg-ink-2 focus-visible:ring-2 focus-visible:ring-ink focus-visible:ring-offset-1 focus-visible:outline-none"
+		>
+			{m.mission_control_segmentation_cta()}
+		</a>
+	</div>
+{/if}