Stage 2: student lesson viewer, Kinescope player, PDF files, prev/next nav, My Courses dashboard

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

@@ -0,0 +1,48 @@
+import { prisma } from "@/lib/prisma";
+import { redirect } from "next/navigation";
+import { notFound } from "next/navigation";
+
+interface Props {
+  params: Promise<{ slug: string }>;
+}
+
+export default async function CoursePage({ params }: Props) {
+  const { slug } = await params;
+
+  const course = await prisma.course.findUnique({
+    where: { slug, published: true },
+    include: {
+      modules: {
+        orderBy: { order: "asc" },
+        include: {
+          lessons: {
+            where: { published: true },
+            orderBy: { order: "asc" },
+            select: { id: true },
+            take: 1,
+          },
+        },
+      },
+    },
+  });
+
+  if (!course) notFound();
+
+  // Redirect to the first published lesson
+  for (const mod of course.modules) {
+    if (mod.lessons.length > 0) {
+      redirect(`/courses/${slug}/lessons/${mod.lessons[0].id}`);
+    }
+  }
+
+  // No lessons yet — show placeholder
+  return (
+    <div className="p-10 text-center">
+      <p className="text-4xl mb-4">📭</p>
+      <p className="font-bold text-lg">Уроков пока нет</p>
+      <p className="text-sm mt-1" style={{ color: "var(--muted-foreground)" }}>
+        Курс в разработке. Загляните позже.
+      </p>
+    </div>
+  );
+}