Implement missing sample data loading and one-time use security

- Fix UI to load server-hosted sample data at startup as per specification
- Add one-time use security: server clears sample data after retrieval
- Ensure React app periodically checks for new sample data availability
- Remove complex same-origin protection in favor of simpler one-time use model
- Improve data security by preventing data persistence after consumption

server.js

@@ -51,7 +51,13 @@ function createApp() {
 
   app.get('/api/v1/sample', (req, res) => {
     try {
-      res.json(sampleData);
+      const dataToReturn = sampleData;
+
+      // Security: Clear the sample data after it's retrieved (one-time use)
+      sampleData = null;
+      console.log('📤 Sample data retrieved and cleared from server memory');
+
+      res.json(dataToReturn);
     } catch (error) {
       res.status(500).json({ error: 'Failed to retrieve sample data' });
     }