implement admin panel with login functionality and dashboard layout

admin/src/Layout/Dashboard.tsx

@@ -0,0 +1,60 @@
+import React from "react";
+import { useState } from "react";
+import { Box, Heading, Text, Flex, Button } from "@chakra-ui/react";
+import Sidebar from "./Sidebar";
+import UserTable from "../components/UserTable";
+import ItemTable from "../components/ItemTable";
+import LockerTable from "../components/LockerTable";
+import LoanTable from "../components/LoanTable";
+
+type DashboardProps = {
+  onLogout?: () => void;
+};
+
+const Dashboard: React.FC<DashboardProps> = ({ onLogout }) => {
+  const userName = localStorage.getItem("userName") || "Admin";
+
+  const [activeView, setActiveView] = useState("");
+
+  return (
+    <Flex h="100vh">
+      <Sidebar
+        viewAusleihen={() => setActiveView("Ausleihen")}
+        viewGegenstaende={() => setActiveView("Gegenstände")}
+        viewSchliessfaecher={() => setActiveView("Schließfächer")}
+        viewUser={() => setActiveView("User")}
+      />
+      <Box flex="1" display="flex" flexDirection="column">
+        <Flex
+          as="header"
+          align="center"
+          justify="space-between"
+          px={6}
+          py={4}
+          borderBottom="1px"
+          borderColor="gray.200"
+          bg="gray.900"
+        >
+          <Heading size="md">Dashboard</Heading>
+          <Flex align="center" gap={6}>
+            <Text fontSize="sm" color="white">
+              Willkommen {userName}, im Admin-Dashboard!
+            </Text>
+            <Button variant="solid" onClick={onLogout}>
+              Logout
+            </Button>
+          </Flex>
+        </Flex>
+        <Box as="main" flex="1" p={6}>
+          {activeView === "" && <Text>Bitte wählen Sie eine Ansicht aus.</Text>}
+          {activeView === "User" && <UserTable />}
+          {activeView === "Ausleihen" && <LoanTable />}
+          {activeView === "Gegenstände" && <ItemTable />}
+          {activeView === "Schließfächer" && <LockerTable />}
+        </Box>
+      </Box>
+    </Flex>
+  );
+};
+
+export default Dashboard;