Clean up admin hub UX: tabs, chrome, and redundant headers.

Wire orphan routes into hub tabs, group Radio into primary/tools rows, show theme/language once on desktop, and remove duplicate page titles under AdminHubChrome.

Co-authored-by: Cursor <[email protected]>

src/app/admin/layout.tsx

@@ -147,8 +147,10 @@ async function Topbar({
 				</span>
 			</div>
 			<div className="flex items-center gap-3">
-				<LanguageSwitcher variant="admin" />
-				<ThemeSwitcher variant="admin" />
+				<div className="flex items-center gap-1.5 lg:hidden">
+					<LanguageSwitcher variant="admin" />
+					<ThemeSwitcher variant="admin" />
+				</div>
 				<span className="text-xs text-[var(--admin-text-muted)]">
 					<strong className="text-[var(--admin-text)]">{staff.username}</strong>
 				</span>