Add optional audio response for students in homework submissions

- Course: add allowAudio toggle (per-course setting, off by default)
- HomeworkSubmission: add audioUrl field
- Student: AudioRecorder in homework form when allowAudio is enabled
- Student: show audio player in submission view and curator feedback view
- Curator: show student audio on submission detail page
- AudioRecorder: accept uploadUrl prop (reused for student/curator)
- API: /api/student/audio-upload route for S3 upload

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

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

@@ -61,7 +61,12 @@ export default async function LessonPage({ params }: Props) {
   const homeworkSubmission = lesson?.homework && session && !isAdmin
     ? await prisma.homeworkSubmission.findFirst({
         where: { homeworkId: lesson.homework.id, userId: session.user.id },
-        include: { feedbacks: { include: { curator: { select: { name: true } } }, orderBy: { createdAt: "desc" } } },
+        include: {
+          feedbacks: {
+            include: { curator: { select: { name: true } } },
+            orderBy: { createdAt: "asc" },
+          },
+        },
       })
     : null;
 
@@ -145,9 +150,16 @@ export default async function LessonPage({ params }: Props) {
             submission={homeworkSubmission ? {
               ...homeworkSubmission,
               files: (homeworkSubmission.files as { name: string; url: string; size: number }[]) ?? [],
+              audioUrl: homeworkSubmission.audioUrl ?? null,
+              feedbacks: homeworkSubmission.feedbacks.map((fb) => ({
+                ...fb,
+                files: (fb.files as { name: string; url: string; size: number }[]) ?? [],
+                audioUrl: fb.audioUrl ?? null,
+              })),
             } : null}
             slug={slug}
             lessonId={lessonId}
+            allowAudio={lesson.module.course.allowAudio}
           />
         </div>
       )}