feat: auto-persist state to localStorage on every change

js/calendar.js

@@ -1,4 +1,4 @@
-import { state } from './app.js';
+import { state, saveState } from './app.js';
 import { getWorkdays, generatePlan } from './algorithm.js';
 import { toggleHoliday, toggleClosure, addHistoryEntries, removeHistoryEntry } from './data.js';
 import { exportSchedule, downloadBlob } from './excel.js';
@@ -99,6 +99,7 @@ export function renderCalendar() {
     const historyWithoutMonth = state.history.filter(h => !h.date.startsWith(prefix));
     currentPlan = generatePlan(workdays, state.employees, historyWithoutMonth);
     addHistoryEntries(state, currentPlan);
+    saveState();
     renderGrid(wrapper, exportBtn);
   });
 
@@ -184,6 +185,7 @@ function renderGrid(wrapper, exportBtn) {
         removeBtn.addEventListener('click', () => {
           if (isHoliday) toggleHoliday(state, iso);
           else toggleClosure(state, iso);
+          saveState();
           renderGrid(wrapper, exportBtn);
         });
         tag.appendChild(removeBtn);
@@ -217,6 +219,7 @@ function renderGrid(wrapper, exportBtn) {
             removeHistoryEntry(state, iso);
             currentPlan = currentPlan.filter(a => a.date !== iso);
           }
+          saveState();
           exportBtn.style.display = currentPlan.length > 0 ? 'inline-block' : 'none';
         });
 
@@ -230,13 +233,13 @@ function renderGrid(wrapper, exportBtn) {
         ftBtn.type = 'button';
         ftBtn.textContent = 'FT';
         ftBtn.style.cssText = 'font-size:9px;padding:1px 4px';
-        ftBtn.addEventListener('click', () => { toggleHoliday(state, iso); renderGrid(wrapper, exportBtn); });
+        ftBtn.addEventListener('click', () => { toggleHoliday(state, iso); saveState(); renderGrid(wrapper, exportBtn); });
 
         const buBtn = document.createElement('button');
         buBtn.type = 'button';
         buBtn.textContent = 'BU';
         buBtn.style.cssText = 'font-size:9px;padding:1px 4px';
-        buBtn.addEventListener('click', () => { toggleClosure(state, iso); renderGrid(wrapper, exportBtn); });
+        buBtn.addEventListener('click', () => { toggleClosure(state, iso); saveState(); renderGrid(wrapper, exportBtn); });
 
         btnRow.append(ftBtn, buBtn);
         cell.appendChild(btnRow);