Fix coin tracker data persistence issue

- Updated API URLs from localhost:3000 to localhost:3001 in script.js
- Added CORS headers to server.js to enable cross-origin requests
- Changed server port from 3000 to 3001 to avoid port conflicts
- Updated CSP in index.html to allow connections to localhost:3001
- Coin tracker entries now persist across page refreshes

html/rechner/server.js

@@ -5,12 +5,20 @@ const fs = require('fs');
 const path = require('path');
 const cron = require('node-cron');
 const app = express();
-const port = 3000;
+const port = 3001;
 
 // Serve static files from the current directory
 app.use(express.static(__dirname));
 app.use(bodyParser.json());
 
+// Add CORS middleware
+app.use((req, res, next) => {
+  res.header('Access-Control-Allow-Origin', '*');
+  res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
+  res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
+  next();
+});
+
 // Create backups directory if it doesn't exist
 const backupDir = path.join(__dirname, 'backups');
 if (!fs.existsSync(backupDir)) {