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/server/routers/file.ts

@@ -1622,4 +1622,62 @@ export const fileRouter = router({
       const { analyzeAllUnanalyzed } = await import('../services/document-analyzer')
       return analyzeAllUnanalyzed()
     }),
+
+  /**
+   * Get document language summary for a specific round.
+   * Returns per-project file language data, flagging non-English documents.
+   */
+  roundLanguageSummary: adminProcedure
+    .input(z.object({ roundId: z.string() }))
+    .query(async ({ ctx, input }) => {
+      const files = await ctx.prisma.projectFile.findMany({
+        where: { roundId: input.roundId },
+        select: {
+          id: true,
+          fileName: true,
+          fileType: true,
+          mimeType: true,
+          pageCount: true,
+          detectedLang: true,
+          langConfidence: true,
+          analyzedAt: true,
+          project: { select: { id: true, title: true } },
+        },
+        orderBy: { createdAt: 'desc' },
+      })
+
+      const totalFiles = files.length
+      const analyzedFiles = files.filter((f) => f.analyzedAt !== null)
+      const nonEnglish = analyzedFiles.filter(
+        (f) => f.detectedLang && f.detectedLang !== 'eng' && f.detectedLang !== 'und' && (f.langConfidence ?? 0) >= 0.4
+      )
+      const unanalyzed = files.filter((f) => f.analyzedAt === null)
+
+      // Group non-English files by project
+      const projectMap = new Map<string, {
+        projectId: string
+        projectTitle: string
+        files: typeof nonEnglish
+      }>()
+      for (const file of nonEnglish) {
+        const existing = projectMap.get(file.project.id)
+        if (existing) {
+          existing.files.push(file)
+        } else {
+          projectMap.set(file.project.id, {
+            projectId: file.project.id,
+            projectTitle: file.project.title,
+            files: [file],
+          })
+        }
+      }
+
+      return {
+        totalFiles,
+        analyzedCount: analyzedFiles.length,
+        unanalyzedCount: unanalyzed.length,
+        nonEnglishCount: nonEnglish.length,
+        flaggedProjects: Array.from(projectMap.values()),
+      }
+    }),
 })