feat: add authentication and admin features

- Added `jose` library for JWT token generation and verification.
- Implemented login functionality with token storage using cookies.
- Created `HeaderAdmin` component for admin panel with login/logout capabilities.
- Developed `LoginForm` component for user authentication.
- Added `Table` component to display data with caching from localStorage.
- Introduced `SubHeaderAdmin` for additional admin actions.
- Enhanced `database.js` with functions for admin login and fetching table data.
- Updated `server.js` to handle new routes for login and table data retrieval.
- Modified `package.json` and `package-lock.json` to include new dependencies.

backend/services/database.js

@@ -2,7 +2,7 @@ import mysql from "mysql2";
 import dotenv from "dotenv";
 dotenv.config();
 
-// Create a MySQL connection pool using environment variables for configuration
+// Ein einzelner Pool reicht; der zweite Pool benutzte fälschlich DB_TABLE als Datenbank
 const pool = mysql
   .createPool({
     host: process.env.DB_HOST,
@@ -32,3 +32,21 @@ export async function query(params) {
     return { success: false };
   }
 }
+
+export async function loginAdmin(username, password) {
+  const [rows] = await pool.query(
+    "SELECT * FROM admin_user WHERE username = ? AND password = ?",
+    [username, password]
+  );
+  if (rows.length > 0) return { success: true };
+  return { success: false };
+}
+
+export async function getTableData() {
+  const [result] = await pool.query("SELECT * FROM lose");
+
+  if (result.length > 0) {
+    return { success: true, data: result };
+  }
+  return { success: false };
+}