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/(student)/courses/[slug]/lessons/[lessonId]/page.tsx

@@ -8,6 +8,7 @@ import { LessonContent } from "@/components/student/lesson-content";
 import { LessonCompleteButton } from "@/components/student/lesson-complete-button";
 import { HomeworkSection } from "@/components/student/homework-section";
 import { LessonComments } from "@/components/student/lesson-comments";
+import { FileFormatBadge } from "@/components/shared/file-format-badge";
 
 interface Props {
   params: Promise<{ slug: string; lessonId: string }>;
@@ -123,7 +124,7 @@ export default async function LessonPage({ params }: Props) {
                 className="flex items-center gap-3 px-4 py-3 text-sm transition-colors hover:[border-color:var(--foreground)]"
                 style={{ border: "2px solid var(--border)" }}
               >
-                <span className="text-lg">📎</span>
+                <FileFormatBadge url={file.url} />
                 <span className="flex-1 font-medium">{file.name}</span>
                 <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
                   {formatSize(file.size)}

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 });
   }