Add update testing functionality

- Add test mode for simulating available updates
- Implement a toggle to enable/disable test mode
- Add test parameter to check-updates endpoint
- Clean up debugging comments
- Create subtle testing UI controls

This enables testing the update functionality without needing
to create a new higher version in the repository.

🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>

server-endpoints.js

@@ -64,7 +64,24 @@ app.get('/api/system/check-updates', async (req, res) => {
     const packageJson = JSON.parse(fs.readFileSync(path.join(__dirname, 'package.json'), 'utf8'));
     const currentVersion = packageJson.version;
     
-    // Fetch latest updates without applying them
+    // Check for test mode flag which forces update availability for testing
+    const testMode = req.query.test === 'true';
+    
+    if (testMode) {
+      // In test mode, always return that an update is available
+      return res.json({
+        status: 'success',
+        data: {
+          updateAvailable: true,
+          currentVersion,
+          remoteVersion: '2.1.0-test',
+          commitsBehind: 1,
+          testMode: true
+        }
+      });
+    }
+    
+    // Normal mode - fetch latest updates without applying them
     await execAsync('git fetch');
     
     // Check if we're behind the remote repository