Add workdays routes to backend and frontend; update routing and UI components for workdays tracking

backend/src/index.js

@@ -78,6 +78,10 @@ app.use('/api/vacation', authenticateToken, vacationRouter);
 const sickRouter = require('./routes/sick');
 app.use('/api/sick', authenticateToken, sickRouter);
 
+// Workdays routes (geschützt) - MIT ID-Hashing
+const workdaysRouter = require('./routes/workdays');
+app.use('/api/workdays', authenticateToken, workdaysRouter);
+
 // Error handling middleware
 app.use((err, req, res, next) => {
   console.error(err.stack);