feat: document language checker on round overview

- New roundLanguageSummary query in file router aggregates per-round document
  language data from existing detectedLang/langConfidence fields
- Document Languages card on round overview tab shows analysis status and
  flags non-English documents grouped by project with confidence scores
- Green border when all documents are English, amber when issues detected
- Project names link to project detail page for easy navigation

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

src/app/(admin)/admin/rounds/[roundId]/page.tsx

@@ -77,6 +77,8 @@ import {
   ArrowRight,
   RotateCcw,
   ListChecks,
+  FileText,
+  Languages,
 } from 'lucide-react'
 import {
   Tooltip,
@@ -1471,6 +1473,9 @@ export default function RoundDetailPage() {
               </Card>
             </AnimatedCard>
           </div>
+
+          {/* Document Language Summary */}
+          <DocumentLanguageSummary roundId={roundId as string} />
         </TabsContent>
 
         {/* ═══════════ PROJECTS TAB ═══════════ */}
@@ -2482,3 +2487,75 @@ export default function RoundDetailPage() {
     </div>
   )
 }
+
+// =============================================================================
+// Document Language Summary — flags non-English docs
+// =============================================================================
+
+const LANG_NAMES: Record<string, string> = {
+  eng: 'English', fra: 'French', deu: 'German', spa: 'Spanish', ita: 'Italian',
+  por: 'Portuguese', nld: 'Dutch', rus: 'Russian', ara: 'Arabic', zho: 'Chinese',
+  jpn: 'Japanese', kor: 'Korean', tur: 'Turkish', pol: 'Polish', ron: 'Romanian',
+  ces: 'Czech', ell: 'Greek', hun: 'Hungarian', swe: 'Swedish', dan: 'Danish',
+  fin: 'Finnish', nor: 'Norwegian', und: 'Unknown',
+}
+
+function DocumentLanguageSummary({ roundId }: { roundId: string }) {
+  const { data, isLoading } = trpc.file.roundLanguageSummary.useQuery(
+    { roundId },
+    { refetchInterval: 60_000 }
+  )
+
+  if (isLoading || !data) return null
+  if (data.totalFiles === 0) return null
+
+  const allGood = data.nonEnglishCount === 0 && data.unanalyzedCount === 0
+
+  return (
+    <Card className={allGood ? 'border-green-200 bg-green-50/30' : data.nonEnglishCount > 0 ? 'border-amber-300 bg-amber-50/30' : ''}>
+      <CardHeader className="pb-2">
+        <CardTitle className="text-sm flex items-center gap-2">
+          <Languages className={cn('h-4 w-4', allGood ? 'text-green-600' : data.nonEnglishCount > 0 ? 'text-amber-600' : 'text-muted-foreground')} />
+          Document Languages
+          {data.nonEnglishCount > 0 && (
+            <Badge variant="destructive" className="text-[10px] px-1.5 py-0">
+              {data.nonEnglishCount} flagged
+            </Badge>
+          )}
+        </CardTitle>
+        <CardDescription className="text-xs">
+          {data.analyzedCount} of {data.totalFiles} documents analyzed
+          {data.unanalyzedCount > 0 && ` — ${data.unanalyzedCount} pending`}
+        </CardDescription>
+      </CardHeader>
+      {data.nonEnglishCount > 0 && (
+        <CardContent className="space-y-2">
+          {data.flaggedProjects.map((project) => (
+            <div key={project.projectId} className="rounded-md border bg-white p-3">
+              <Link
+                href={`/admin/projects/${project.projectId}` as Route}
+                className="text-sm font-medium text-primary hover:underline"
+              >
+                {project.projectTitle}
+              </Link>
+              <div className="mt-1.5 space-y-1">
+                {project.files.map((file) => (
+                  <div key={file.id} className="flex items-center justify-between text-xs">
+                    <div className="flex items-center gap-1.5 min-w-0">
+                      <FileText className="h-3 w-3 text-muted-foreground shrink-0" />
+                      <span className="truncate">{file.fileName}</span>
+                    </div>
+                    <Badge variant="outline" className="text-[10px] px-1.5 py-0 shrink-0 ml-2 border-amber-300 text-amber-700">
+                      {LANG_NAMES[file.detectedLang ?? ''] || file.detectedLang}
+                      {file.langConfidence != null && ` (${Math.round(file.langConfidence * 100)}%)`}
+                    </Badge>
+                  </div>
+                ))}
+              </div>
+            </div>
+          ))}
+        </CardContent>
+      )}
+    </Card>
+  )
+}