fix: wire year selector and fix shallow copy in loadPlanFromHistory

js/calendar.js

@@ -82,6 +82,12 @@ export function renderCalendar() {
     renderGrid(wrapper, exportBtn);
   });
 
+  yearSel.addEventListener('change', () => {
+    currentYear = parseInt(yearSel.value);
+    loadPlanFromHistory();
+    renderGrid(wrapper, exportBtn);
+  });
+
   genBtn.addEventListener('click', () => {
     if (state.employees.length === 0) {
       alert('Bitte zuerst Mitarbeiter hinzufügen.');
@@ -106,7 +112,7 @@ function loadPlanFromHistory() {
   const prefix = currentYear + '-' + String(currentMonth).padStart(2,'0');
   currentPlan = state.history
     .filter(h => h.date.startsWith(prefix))
-    .slice();
+    .map(h => ({ ...h }));
 }
 
 function renderGrid(wrapper, exportBtn) {