feat: auto-enroll new signups into free course obsidian-start (freemium)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/api/register/route.ts

@@ -76,7 +76,7 @@ export async function POST(request: NextRequest) {
     process.env.BETTER_AUTH_URL ??
     `https://${request.headers.get("host")}`;
 
-  return auth.handler(
+  const response = await auth.handler(
     new Request(`${baseUrl}/api/auth/sign-up/email`, {
       method: "POST",
       headers: new Headers({
@@ -86,4 +86,41 @@ export async function POST(request: NextRequest) {
       body: JSON.stringify({ name, email, password, callbackURL: "/dashboard" }),
     })
   );
+
+  // Freemium: при успешной регистрации авто-записываем в бесплатный курс.
+  // Не валим регистрацию, если enroll не удался.
+  if (response.ok && email) {
+    try {
+      const freeSlug = process.env.FREE_COURSE_SLUG ?? "obsidian-start";
+      const [user, course] = await Promise.all([
+        prisma.user.findFirst({
+          where: { email: { equals: email, mode: "insensitive" } },
+          select: { id: true },
+        }),
+        prisma.course.findUnique({
+          where: { slug: freeSlug },
+          select: { id: true },
+        }),
+      ]);
+      if (user && course) {
+        await prisma.courseEnrollment.upsert({
+          where: { userId_courseId: { userId: user.id, courseId: course.id } },
+          update: {},
+          create: { userId: user.id, courseId: course.id },
+        });
+        await prisma.accessLog.create({
+          data: {
+            courseId: course.id,
+            userId: user.id,
+            action: "granted",
+            method: "free-signup",
+          },
+        });
+      }
+    } catch (e) {
+      console.error("free-enroll failed", e);
+    }
+  }
+
+  return response;
 }