Remember card sort (e.g. by due date) across reloads (#5886)

The card sort was stored only in a Meteor Session variable, which is in-memory
and reset on page reload, so a chosen sort (such as by due date) reverted to the
default. Persist the sort to localStorage when set/reset, restore it into Session
when the board header loads (so the sort icon is correct too), and read it as a
fallback when sorting cards.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

client/components/boards/boardHeader.js

@@ -17,6 +17,21 @@ const UPCLS = 'fa-sort-up';
 */
 const sortCardsBy = new ReactiveVar('');
 
+// Persist the card sort so it survives a page reload. Session is in-memory and
+// is reset on reload, which is why "sort by due date" kept reverting to the
+// default. See https://github.com/wekan/wekan/issues/5886
+const CARDS_SORT_BY_STORAGE_KEY = 'wekan-cards-sortBy';
+function setCardsSortBy(sortBy) {
+  Session.set('sortBy', sortBy);
+  try {
+    if (sortBy) {
+      window.localStorage.setItem(CARDS_SORT_BY_STORAGE_KEY, JSON.stringify(sortBy));
+    } else {
+      window.localStorage.removeItem(CARDS_SORT_BY_STORAGE_KEY);
+    }
+  } catch (e) {}
+}
+
 Template.boardChangeTitlePopup.events({
   async submit(event, templateInstance) {
     event.preventDefault();
@@ -41,6 +56,16 @@ Template.boardChangeTitlePopup.events({
 
 Template.boardHeaderBar.onCreated(function () {
   Meteor.subscribe('tableVisibilityModeSettings');
+  // Restore the persisted card sort after a reload (Session is in-memory), so
+  // both the sorting and the sort icon are remembered. See #5886.
+  if (!Session.get('sortBy')) {
+    try {
+      const stored = window.localStorage.getItem(CARDS_SORT_BY_STORAGE_KEY);
+      if (stored) {
+        Session.set('sortBy', JSON.parse(stored));
+      }
+    } catch (e) {}
+  }
 });
 
 Template.boardHeaderBar.helpers({
@@ -171,7 +196,7 @@ Template.boardHeaderBar.events({
     Filter.reset();
   },
   'click .js-sort-reset'() {
-    Session.set('sortBy', '');
+    setCardsSortBy('');
   },
   'click .js-open-search-view'() {
     const sidebar = getSidebarInstance();
@@ -529,7 +554,7 @@ Template.cardsSortPopup.events({
     const sortBy = {
       dueAt: 1,
     };
-    Session.set('sortBy', sortBy);
+    setCardsSortBy(sortBy);
     sortCardsBy.set(TAPi18n.__('due-date'));
     Popup.back();
   },
@@ -537,7 +562,7 @@ Template.cardsSortPopup.events({
     const sortBy = {
       title: 1,
     };
-    Session.set('sortBy', sortBy);
+    setCardsSortBy(sortBy);
     sortCardsBy.set(TAPi18n.__('title'));
     Popup.back();
   },
@@ -545,7 +570,7 @@ Template.cardsSortPopup.events({
     const sortBy = {
       createdAt: 1,
     };
-    Session.set('sortBy', sortBy);
+    setCardsSortBy(sortBy);
     sortCardsBy.set(TAPi18n.__('date-created-newest-first'));
     Popup.back();
   },
@@ -553,7 +578,7 @@ Template.cardsSortPopup.events({
     const sortBy = {
       createdAt: -1,
     };
-    Session.set('sortBy', sortBy);
+    setCardsSortBy(sortBy);
     sortCardsBy.set(TAPi18n.__('date-created-oldest-first'));
     Popup.back();
   },

client/components/lists/listBody.js

@@ -324,7 +324,20 @@ Template.listBody.helpers({
     const tpl = Template.instance();
     const limit = tpl.cardlimit.get();
     const defaultSort = { sort: 1 };
-    const sortBy = Session.get('sortBy') ? Session.get('sortBy') : defaultSort;
+    // Session is reset on page reload; fall back to the persisted card sort so a
+    // chosen sort (e.g. by due date) is remembered across reloads (#5886).
+    let sortBy = Session.get('sortBy');
+    if (!sortBy) {
+      try {
+        const stored = window.localStorage.getItem('wekan-cards-sortBy');
+        if (stored) {
+          sortBy = JSON.parse(stored);
+        }
+      } catch (e) {}
+    }
+    if (!sortBy) {
+      sortBy = defaultSort;
+    }
     const selector = {
       listId: Template.currentData()._id,
       archived: false,