🔧 Fix CORS: Allow all origins for development

- Simplified CORS configuration to allow all origins (*)
- Removed origin restrictions for easier development
- Fixed CORS preflight request handling
- Now allows requests from any domain including 192.168.1.96

server.js

@@ -48,6 +48,23 @@ const io = new Server(server, {
 // MIDDLEWARE SETUP
 // ============================================================================
 
+// CORS Configuration - Allow all origins for development
+app.use((req, res, next) => {
+    // Allow all origins
+    res.setHeader('Access-Control-Allow-Origin', '*');
+    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS, PATCH');
+    res.setHeader('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization, X-API-Key');
+    res.setHeader('Access-Control-Max-Age', '86400'); // 24 hours
+
+    // Handle preflight requests
+    if (req.method === 'OPTIONS') {
+        res.status(200).end();
+        return;
+    }
+
+    next();
+});
+
 // Body Parser Middleware
 app.use(express.json({ limit: '10mb' }));
 app.use(express.urlencoded({ extended: true, limit: '10mb' }));
@@ -57,7 +74,7 @@ app.use(session({
     secret: process.env.SESSION_SECRET || 'kjhdizr3lhwho8fpjslgf825ß0hsd',
     resave: false,
     saveUninitialized: false,
-    cookie: { 
+    cookie: {
         secure: false, // Set to true when using HTTPS
         maxAge: 24 * 60 * 60 * 1000, // 24 hours
         httpOnly: true // Security: prevent XSS attacks
@@ -205,7 +222,7 @@ app.use('/login', express.static('public'));
  */
 io.on('connection', (socket) => {
     // Client connected - connection is established
-    
+
     socket.on('disconnect', () => {
         // Client disconnected - cleanup if needed
     });
@@ -271,13 +288,13 @@ server.listen(port, () => {
  */
 process.on('SIGINT', async () => {
     console.log('\n🛑 Server wird heruntergefahren...');
-    
+
     // Close server gracefully
     server.close(() => {
         console.log('✅ Server erfolgreich heruntergefahren');
         process.exit(0);
     });
-    
+
     // Force exit after 5 seconds if graceful shutdown fails
     setTimeout(() => {
         console.log('⚠️ Forced shutdown after timeout');