feat(admin): add OCR training card to admin/system page

- TrainingHistory.svelte: responsive table with status badges
  (green/red/animated pulse), keyed iteration, empty-state row
- OcrTrainingCard.svelte: shows available blocks/docs, disabled states
  (< 5 blocks, service down), in-flight "…" state, 5s success message,
  embeds TrainingHistory
- Wired into admin/system/+page.svelte via fetchTrainingInfo() in $effect
- Regenerated api.ts with OcrTrainingRun + TrainingInfoResponse types
- TRAINING_ALREADY_RUNNING error code in errors.ts + de/en/es translations
- 7 OcrTrainingCard Vitest tests

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

frontend/src/routes/admin/system/+page.svelte

@@ -1,6 +1,12 @@
 <script lang="ts">
 import { onDestroy } from 'svelte';
 import { m } from '$lib/paraglide/messages.js';
+import OcrTrainingCard from '$lib/components/OcrTrainingCard.svelte';
+import type { components } from '$lib/generated/api.js';
+
+type TrainingInfo = components['schemas']['TrainingInfoResponse'];
+
+let trainingInfo: TrainingInfo | null = $state(null);
 
 let backfillResult: number | null = $state(null);
 let backfillLoading = $state(false);
@@ -51,8 +57,16 @@ async function triggerImport() {
 	}
 }
 
+async function fetchTrainingInfo() {
+	const res = await fetch('/api/ocr/training-info');
+	if (res.ok) {
+		trainingInfo = await res.json();
+	}
+}
+
 $effect(() => {
 	fetchImportStatus();
+	fetchTrainingInfo();
 });
 
 onDestroy(() => stopPolling());
@@ -88,6 +102,9 @@ async function backfillFileHashes() {
 
 <div class="flex-1 overflow-y-auto p-6">
 	<div class="mx-auto max-w-2xl space-y-5">
+		<!-- OCR Training -->
+		<OcrTrainingCard trainingInfo={trainingInfo} />
+
 		<!-- Backfill versions -->
 		<div class="rounded-sm border border-line bg-surface p-6 shadow-sm">
 			<h2 class="mb-1 font-sans text-sm font-bold text-ink">{m.admin_system_backfill_heading()}</h2>

frontend/src/routes/admin/system/page.svelte.spec.ts

@@ -78,6 +78,8 @@ describe('Admin system page — mass import card', () => {
 					startedAt: null
 				})
 			})
+			// training info fetch → empty
+			.mockResolvedValueOnce({ ok: true, json: async () => ({}) })
 			// trigger POST → returns RUNNING immediately
 			.mockResolvedValueOnce({
 				ok: true,