feat: initialize CalBook project with comprehensive scheduling, admin, and deployment infrastructure

app/(admin)/admin/layout.tsx

@@ -0,0 +1,26 @@
+import { getServerSession } from "next-auth";
+import { redirect } from "next/navigation";
+import { authOptions } from "@/lib/auth/options";
+import { AdminLayoutClientShell } from "@/components/admin/admin-nav";
+import { SETTING_KEYS } from "@/lib/constants";
+import { getSetting } from "@/lib/settings";
+import { AccentColorScript } from "@/components/layout/accent-color";
+
+export default async function AdminLayout({ children }: { children: React.ReactNode }) {
+  const session = await getServerSession(authOptions);
+  if (!session?.user) redirect("/anmelden");
+  if (session.user.role !== "ADMIN") redirect("/anmelden");
+
+  let accentColor = "#4f46e5";
+  try {
+    const color = await getSetting(SETTING_KEYS.BRANDING_ACCENT_COLOR);
+    if (color && /^#[0-9a-fA-F]{6}$/.test(color)) accentColor = color;
+  } catch { /* default */ }
+
+  return (
+    <>
+      <AccentColorScript color={accentColor} />
+      <AdminLayoutClientShell>{children}</AdminLayoutClientShell>
+    </>
+  );
+}