v3: added site-wide categories, added admin category management, various visual fixes

api/lib/reserved-slugs.ts

@@ -0,0 +1,33 @@
+// Top-level path segments that already have meaning in the SPA router
+// (see src/App.tsx) plus a few reserved for infrastructure. Category slugs
+// live at the URL root (e.g. /music), so they must never collide with these.
+export const RESERVED_SLUGS: readonly string[] = [
+  "~",
+  "dumps",
+  "users",
+  "playlists",
+  "search",
+  "login",
+  "register",
+  "notifications",
+  "reset-password",
+  "manage",
+  "api",
+  "assets",
+];
+
+// Lowercase alphanumerics, hyphen-separated, no leading/trailing/double hyphen.
+export const CATEGORY_SLUG_RE = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
+
+export function isValidSlugFormat(slug: string): boolean {
+  return CATEGORY_SLUG_RE.test(slug);
+}
+
+export function isReservedSlug(slug: string): boolean {
+  return RESERVED_SLUGS.includes(slug);
+}
+
+/** A slug is available when it is well-formed and not reserved. */
+export function isSlugAvailable(slug: string): boolean {
+  return isValidSlugFormat(slug) && !isReservedSlug(slug);
+}