feat: complete MVP foundation auth and dashboard

app/dashboard/layout.tsx

@@ -0,0 +1,25 @@
+import { redirect } from "next/navigation";
+
+import { DashboardSidebar } from "@/components/dashboard-sidebar";
+import { getCurrentMockSession } from "@/lib/mock-session";
+import { getDashboardRedirectPath } from "@/lib/route-guards";
+
+export default async function DashboardLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  const session = await getCurrentMockSession();
+  const redirectPath = getDashboardRedirectPath(session);
+
+  if (redirectPath || !session) {
+    redirect(redirectPath ?? "/");
+  }
+
+  return (
+    <div className="min-h-dvh bg-background md:flex">
+      <DashboardSidebar session={session} />
+      <div className="min-w-0 flex-1">{children}</div>
+    </div>
+  );
+}