feat: add authentication and user management features

- Implemented AuthButton component for Discord sign-in and sign-out functionality.
- Created CopyButton component for copying server IP addresses.
- Developed EventCard and GradeCard components for displaying events and grades.
- Added Footer and Navbar components for site navigation and information.
- Introduced PurchaseButton for handling grade purchases with Stripe integration.
- Created SectionHeader component for consistent section titles.
- Implemented session management with SessionProvider for NextAuth.
- Set up PostgreSQL database with Docker and Prisma for data management.
- Added admin guard functionality to restrict access to certain routes.
- Configured NextAuth with Discord provider for user authentication.
- Defined Prisma schema for user, admin, grade, event, and purchase models.
- Seeded database with initial grades and events data.
- Added SVG hero image for the landing page.
- Extended NextAuth types to include additional user properties.

app/api/admin/grades/route.ts

@@ -0,0 +1,32 @@
+import { db } from "@/lib/db";
+import { requireAdmin } from "@/lib/admin";
+
+export const dynamic = "force-dynamic";
+
+export async function GET() {
+  const guard = await requireAdmin();
+  if (!guard.ok) return guard.response;
+
+  const grades = await db.grade.findMany({ orderBy: { price: "asc" } });
+  return Response.json(grades);
+}
+
+export async function POST(request: Request) {
+  const guard = await requireAdmin();
+  if (!guard.ok) return guard.response;
+
+  const body = await request.json();
+  const name = body?.name?.toString().trim();
+  const price = Number(body?.price);
+  const description = body?.description?.toString().trim();
+
+  if (!name || Number.isNaN(price) || !description) {
+    return Response.json({ error: "Invalid payload" }, { status: 400 });
+  }
+
+  const grade = await db.grade.create({
+    data: { name, price, description },
+  });
+
+  return Response.json(grade);
+}