Add admin Articles (CRUD) + Bans resources

- Articles: list / new / edit / delete (websiteArticles), unique-slug
  generation via slugify() (pure, unit-tested); staff-gated server actions.
- Bans: list active bans (ban_expire > now), create ban (writes the bans row +
  RCON disconnect) with type/duration/reason, lift ban; staff-gated actions.
- Admin nav extended (Articles, Bans).

Verified: tsc exit 0, vitest 48/48, next build exit 0 (7 /admin routes).

src/app/admin/articles/page.tsx

@@ -0,0 +1,41 @@
+import Link from "next/link";
+import { prisma } from "@/lib/prisma";
+
+export const dynamic = "force-dynamic";
+
+export default async function AdminArticles() {
+  const articles = await prisma.websiteArticles.findMany({
+    orderBy: { createdAt: "desc" },
+    select: { id: true, title: true, slug: true, createdAt: true },
+    take: 50,
+  });
+
+  return (
+    <main>
+      <div style={{ display: "flex", alignItems: "center", gap: "1rem" }}>
+        <h1 style={{ flex: 1 }}>Articles</h1>
+        <Link href="/admin/articles/new">+ New article</Link>
+      </div>
+      <table style={{ width: "100%", borderCollapse: "collapse" }}>
+        <thead>
+          <tr style={{ textAlign: "left", color: "var(--muted)" }}>
+            <th>Title</th>
+            <th>Slug</th>
+            <th>Created</th>
+          </tr>
+        </thead>
+        <tbody>
+          {articles.map((a) => (
+            <tr key={String(a.id)} style={{ borderTop: "1px solid var(--border)" }}>
+              <td>
+                <Link href={`/admin/articles/${a.id}`}>{a.title}</Link>
+              </td>
+              <td className="muted">{a.slug}</td>
+              <td className="muted">{a.createdAt ? a.createdAt.toISOString().slice(0, 10) : ""}</td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </main>
+  );
+}