Add lesson comments (Stage 6)

- LessonComment CRUD: addComment / deleteComment server actions
- LessonComments client component with form, avatar, delete
- Comments section at bottom of lesson page (enrolled users only)
- Soft-delete support, moderation for curator/admin
- ROADMAP: moved Квизы to end (Stage 11), marked Stage 7 done

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

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

@@ -7,6 +7,7 @@ import { KinescopePlayer } from "@/components/player/kinescope-player";
 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";
 
 interface Props {
   params: Promise<{ slug: string; lessonId: string }>;
@@ -18,7 +19,7 @@ export default async function LessonPage({ params }: Props) {
   const session = await auth.api.getSession({ headers: await headers() });
   const isAdmin = session?.user.role === "admin";
 
-  const [lesson, progress] = await Promise.all([
+  const [lesson, progress, comments] = await Promise.all([
     prisma.lesson.findUnique({
       where: { id: lessonId, ...(isAdmin ? {} : { published: true }) },
       include: {
@@ -49,6 +50,11 @@ export default async function LessonPage({ params }: Props) {
           where: { userId_lessonId: { userId: session.user.id, lessonId } },
         })
       : null,
+    prisma.lessonComment.findMany({
+      where: { lessonId },
+      orderBy: { createdAt: "asc" },
+      include: { user: { select: { id: true, name: true } } },
+    }),
   ]);
 
   // Fetch homework submission for this student
@@ -179,6 +185,25 @@ export default async function LessonPage({ params }: Props) {
           </div>
         )}
       </div>
+
+      {/* Comments */}
+      {session && (
+        <div
+          className="mt-10 pt-8"
+          style={{ borderTop: "2px solid var(--border)" }}
+        >
+          <p className="text-xs font-bold uppercase tracking-widest mb-6" style={{ color: "var(--muted-foreground)" }}>
+            Обсуждение ({comments.filter((c) => !c.deleted).length})
+          </p>
+          <LessonComments
+            lessonId={lessonId}
+            slug={slug}
+            comments={comments}
+            currentUserId={session.user.id}
+            currentUserRole={session.user.role ?? "student"}
+          />
+        </div>
+      )}
     </article>
   );
 }