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/lib/format.ts

@@ -12,6 +12,19 @@ export function avatarImageUrl(
   return `${base}${sep}${params.toString()}`;
 }
 
+/** URL-safe slug from a title (lowercase, ascii, hyphenated). */
+export function slugify(input: string): string {
+  // NFKD splits accented letters into base + combining mark; the combining
+  // marks (and any other non-alphanumerics) are then collapsed to hyphens.
+  const slug = input
+    .toLowerCase()
+    .normalize("NFKD")
+    .replace(/[^a-z0-9]+/g, "-")
+    .replace(/^-+|-+$/g, "")
+    .slice(0, 255);
+  return slug || "article";
+}
+
 /** Trim text to `max` chars on a word boundary, adding an ellipsis. */
 export function excerpt(text: string, max = 160): string {
   if (text.length <= max) return text;