Add labeled file materials with format badge

- Store human-readable label in LessonFile.name via optional label field on upload
- Add PATCH endpoint to rename existing files inline
- Admin: label input before upload, click-to-edit inline rename
- Student: colored format badge (PDF/DOCX/XLSX/ZIP/etc) replaces paperclip emoji

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

src/app/api/admin/lesson-files/route.ts

@@ -5,15 +5,21 @@ import { prisma } from "@/lib/prisma";
 import { uploadFile, deleteFile } from "@/lib/s3";
 import { randomUUID } from "crypto";
 
-export async function POST(req: NextRequest) {
+async function requireAdmin(req: NextRequest) {
   const session = await auth.api.getSession({ headers: await headers() });
-  if (!session || session.user.role !== "admin") {
+  if (!session || session.user.role !== "admin") return null;
+  return session;
+}
+
+export async function POST(req: NextRequest) {
+  if (!await requireAdmin(req)) {
     return NextResponse.json({ error: "Forbidden" }, { status: 403 });
   }
 
   const form = await req.formData();
   const file = form.get("file") as File | null;
   const lessonId = form.get("lessonId") as string | null;
+  const label = (form.get("label") as string | null)?.trim() || null;
   if (!file || !lessonId) return NextResponse.json({ error: "Missing fields" }, { status: 400 });
 
   const ext = file.name.split(".").pop() ?? "bin";
@@ -22,15 +28,30 @@ export async function POST(req: NextRequest) {
   const url = await uploadFile(key, buffer, file.type);
 
   const lessonFile = await prisma.lessonFile.create({
-    data: { lessonId, name: file.name, url, size: file.size },
+    data: { lessonId, name: label ?? file.name, url, size: file.size },
   });
 
   return NextResponse.json(lessonFile);
 }
 
+export async function PATCH(req: NextRequest) {
+  if (!await requireAdmin(req)) {
+    return NextResponse.json({ error: "Forbidden" }, { status: 403 });
+  }
+
+  const { fileId, label } = await req.json();
+  if (!fileId || typeof label !== "string") {
+    return NextResponse.json({ error: "Missing fields" }, { status: 400 });
+  }
+  const updated = await prisma.lessonFile.update({
+    where: { id: fileId },
+    data: { name: label.trim() || undefined },
+  });
+  return NextResponse.json(updated);
+}
+
 export async function DELETE(req: NextRequest) {
-  const session = await auth.api.getSession({ headers: await headers() });
-  if (!session || session.user.role !== "admin") {
+  if (!await requireAdmin(req)) {
     return NextResponse.json({ error: "Forbidden" }, { status: 403 });
   }