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/[id]/page.tsx

@@ -0,0 +1,42 @@
+import Link from "next/link";
+import { notFound } from "next/navigation";
+import { deleteArticle, updateArticle } from "@/actions/admin-articles";
+import { prisma } from "@/lib/prisma";
+
+export const dynamic = "force-dynamic";
+
+export default async function EditArticle({
+  params,
+}: {
+  params: Promise<{ id: string }>;
+}) {
+  const { id } = await params;
+  let article: Awaited<ReturnType<typeof prisma.websiteArticles.findUnique>> = null;
+  try {
+    article = await prisma.websiteArticles.findUnique({ where: { id: BigInt(id) } });
+  } catch {
+    notFound();
+  }
+  if (!article) notFound();
+
+  return (
+    <main>
+      <p className="muted">
+        <Link href="/admin/articles">← Articles</Link>
+      </p>
+      <h1>Edit article</h1>
+      <form action={updateArticle} className="card" style={{ display: "grid", gap: "0.6rem" }}>
+        <input type="hidden" name="id" value={String(article.id)} />
+        <input name="title" defaultValue={article.title} required />
+        <input name="image" defaultValue={article.image} placeholder="Image URL" />
+        <textarea name="shortStory" defaultValue={article.shortStory} rows={2} />
+        <textarea name="fullStory" defaultValue={article.fullStory} rows={10} />
+        <button type="submit">Save</button>
+      </form>
+      <form action={deleteArticle} style={{ marginTop: "1rem" }}>
+        <input type="hidden" name="id" value={String(article.id)} />
+        <button type="submit">Delete article</button>
+      </form>
+    </main>
+  );
+}