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.

components/navbar.tsx

@@ -0,0 +1,49 @@
+import Link from "next/link";
+import AuthButton from "@/components/auth-button";
+
+const navLinks = [
+  { label: "Presentation", href: "#presentation" },
+  { label: "Grades", href: "#grades" },
+  { label: "Events", href: "#events" },
+  { label: "Discord", href: "#discord" },
+];
+
+export default function Navbar() {
+  return (
+    <header className="sticky top-0 z-40 w-full border-b border-white/5 bg-slate-950/70 backdrop-blur">
+      <div className="mx-auto flex w-full max-w-6xl items-center justify-between px-6 py-4">
+        <Link href="/" className="flex items-center gap-3">
+          <span className="flex h-9 w-9 items-center justify-center rounded-2xl bg-linear-to-br from-violet-600 via-indigo-500 to-cyan-400 text-sm font-bold text-slate-950 shadow-[0_12px_30px_rgba(59,130,246,0.4)]">
+            BU
+          </span>
+          <div className="flex flex-col">
+            <span className="text-sm font-semibold uppercase tracking-[0.3em] text-white">
+              BinouzUHC
+            </span>
+            <span className="text-xs text-slate-400">UHC PvP 1.8.X</span>
+          </div>
+        </Link>
+        <nav className="hidden items-center gap-6 text-xs uppercase tracking-[0.25em] text-slate-300 md:flex">
+          {navLinks.map((link) => (
+            <a
+              key={link.href}
+              href={link.href}
+              className="transition hover:text-white"
+            >
+              {link.label}
+            </a>
+          ))}
+        </nav>
+        <div className="flex items-center gap-3">
+          <a
+            href="#grades"
+            className="hidden rounded-full border border-white/10 px-4 py-2 text-[10px] uppercase tracking-[0.3em] text-slate-300 transition hover:border-white/30 hover:text-white lg:inline-flex"
+          >
+            Boutique
+          </a>
+          <AuthButton compact />
+        </div>
+      </div>
+    </header>
+  );
+}