fix: keep iCal subscriptions on refresh, rename calendars of any colour

- send a calendar's colour only when the user changed it: Stalwart 1.0
  accepts only #rgb, #rrggbb or a CSS name, so renaming a calendar that
  another client coloured with an 8-digit hex (Apple Calendar) failed
- "Refresh cached data" kept nothing of the calendar store's persisted
  state, so it deleted the user's iCal subscriptions, which exist only
  there; keep them and drop the rest
- show a notice with a retry when the task list fails to load; it keeps
  the tasks it had
- treat a method-level error on creating a task as a failure with its
  JMAP type instead of "no id returned"

components/calendar/__tests__/calendar-load-error-notice.test.tsx

@@ -14,4 +14,9 @@ describe('CalendarLoadErrorNotice', () => {
     fireEvent.click(screen.getByRole('button', { name: 'retry' }));
     expect(onRetry).toHaveBeenCalledTimes(1);
   });
+
+  it('says the task list may be out of date for a failed task load', () => {
+    render(<CalendarLoadErrorNotice what="tasks" onRetry={vi.fn()} />);
+    expect(screen.getByRole('alert')).toHaveTextContent('tasks_load_failed');
+  });
 });

components/calendar/calendar-app.tsx

@@ -65,7 +65,7 @@ import { getClientByLocalAccountId } from "@/stores/client-registry";
 import { useCalendarErrorMessage } from "@/hooks/use-calendar-error-message";
 import { getEventStartDate } from "@/lib/calendar-utils";
 import { displayNow } from "@/lib/timezone";
-import { useTaskStore } from "@/stores/task-store";
+import { TASKS_LOAD_ERROR, useTaskStore } from "@/stores/task-store";
 import { useContactStore } from "@/stores/contact-store";
 import { cn } from "@/lib/utils";
 import type { Calendar, CalendarEvent, CalendarParticipant, CalendarRights } from "@/lib/jmap/types";
@@ -1542,6 +1542,9 @@ export function CalendarApp({ linkSegments: routeSegments }: CalendarAppProps =
         case "tasks":
           return (
             <div className="flex flex-col h-full">
+              {taskStore.error === TASKS_LOAD_ERROR && (
+                <CalendarLoadErrorNotice what="tasks" onRetry={() => { if (client) void fetchTasksFn(client); }} />
+              )}
               <TaskToolbar
                 filter={taskStore.filter}
                 showCompleted={taskStore.showCompleted}

components/calendar/calendar-load-error-notice.tsx

@@ -5,19 +5,21 @@ import { AlertTriangle } from "@/components/icons";
 import { Button } from "@/components/ui/button";
 
 interface CalendarLoadErrorNoticeProps {
+  /** What failed to load: the visible range of events, or the task list. */
+  what?: "events" | "tasks";
   onRetry: () => void;
 }
 
 /**
- * Shown above the grid while the visible range could not be loaded. The grid
- * keeps the events it had, so this says why they may be out of date.
+ * Shown above the grid (or the task list) while it could not be loaded. It
+ * keeps what it had, so this says why that may be out of date.
  */
-export function CalendarLoadErrorNotice({ onRetry }: CalendarLoadErrorNoticeProps) {
+export function CalendarLoadErrorNotice({ what = "events", onRetry }: CalendarLoadErrorNoticeProps) {
   const t = useTranslations("calendar.status");
   return (
     <div role="alert" className="flex items-center gap-2 border-b border-border bg-warning/10 px-4 py-2 text-sm">
       <AlertTriangle className="h-4 w-4 flex-shrink-0 text-warning" />
-      <span className="min-w-0 flex-1">{t("events_load_failed")}</span>
+      <span className="min-w-0 flex-1">{what === "tasks" ? t("tasks_load_failed") : t("events_load_failed")}</span>
       <Button variant="outline" size="sm" onClick={onRetry}>
         {t("retry")}
       </Button>

components/settings/__tests__/calendar-management-settings.test.tsx

@@ -0,0 +1,56 @@
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { CalendarManagementSettings } from '../calendar-management-settings';
+import { useCalendarStore } from '@/stores/calendar-store';
+import { useAuthStore } from '@/stores/auth-store';
+import { CALENDAR_COLORS } from '@/lib/shared-calendar-colors';
+import type { Calendar } from '@/lib/jmap/types';
+
+// Stalwart 1.0 accepts a calendar colour only as #rgb, #rrggbb or a CSS name
+// (calendar/set.rs); 0.16 took anything shorter than 16 characters. Renaming
+// a calendar another client coloured with an 8-digit hex (Apple Calendar)
+// sent that colour back and failed on 1.0.
+
+vi.mock('../settings-section', async (importOriginal) => ({
+  ...(await importOriginal<typeof import('../settings-section')>()),
+  SettingsSection: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+}));
+
+const appleColored = {
+  id: 'cal', name: 'Home', color: '#FF2968FF', isDefault: true, isShared: false, shareWith: null,
+  myRights: { mayShare: true, mayDelete: true, mayWriteAll: true },
+} as unknown as Calendar;
+
+describe('CalendarManagementSettings rename', () => {
+  let updateCalendar: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    updateCalendar = vi.fn().mockResolvedValue(undefined);
+    // No server URL: the CalDAV discovery stays out of it.
+    useAuthStore.setState({ client: { getAccountId: () => 'acct-1' }, serverUrl: null, username: null } as never);
+    useCalendarStore.setState({ calendars: [appleColored], icalSubscriptions: [], updateCalendar } as never);
+  });
+
+  function openEditor() {
+    render(<CalendarManagementSettings />);
+    fireEvent.click(screen.getByTitle('edit'));
+  }
+
+  it('sends the new name without the colour it did not change, for Stalwart 1.0', async () => {
+    openEditor();
+    fireEvent.change(screen.getByDisplayValue('Home'), { target: { value: 'Family' } });
+    fireEvent.click(screen.getByText('save'));
+
+    await waitFor(() => expect(updateCalendar).toHaveBeenCalledTimes(1));
+    expect(updateCalendar.mock.calls[0].slice(1)).toEqual(['cal', { name: 'Family' }]);
+  });
+
+  it('sends a colour the user picked', async () => {
+    openEditor();
+    fireEvent.click(screen.getByLabelText(CALENDAR_COLORS[0]));
+    fireEvent.click(screen.getByText('save'));
+
+    await waitFor(() => expect(updateCalendar).toHaveBeenCalledTimes(1));
+    expect(updateCalendar.mock.calls[0].slice(1)).toEqual(['cal', { name: 'Home', color: CALENDAR_COLORS[0] }]);
+  });
+});

components/settings/calendar-management-settings.tsx

@@ -315,11 +315,21 @@ export function CalendarManagementSettings() {
     }
   };
 
-  const handleUpdate = async (calendarId: string, data: { name: string; color: string }) => {
+  const handleUpdate = async (
+    calendarId: string,
+    data: { name: string; color: string },
+    shownColor: string,
+  ) => {
     if (!client) return;
     setIsLoading(true);
     try {
-      await updateCalendar(client, calendarId, { name: data.name, color: data.color });
+      // The colour only when the user changed it: Stalwart 1.0 accepts only
+      // #rgb, #rrggbb or a CSS colour name, so sending back one another
+      // client stored (an 8-digit hex from Apple Calendar) failed the rename.
+      await updateCalendar(client, calendarId, {
+        name: data.name,
+        ...(data.color !== shownColor ? { color: data.color } : {}),
+      });
       setEditingId(null);
       toast.success(t('calendar_updated'));
     } catch {
@@ -417,7 +427,7 @@ export function CalendarManagementSettings() {
               <CalendarEditForm
                 key={cal.id}
                 initial={{ name: cal.name, color }}
-                onSave={(data) => handleUpdate(cal.id, data)}
+                onSave={(data) => handleUpdate(cal.id, data, color)}
                 onCancel={() => setEditingId(null)}
                 isLoading={isLoading}
               />

lib/__tests__/clear-cached-data.test.ts

@@ -49,4 +49,22 @@ describe('clearCachedData', () => {
     clearCachedData();
     expect(reload).toHaveBeenCalledOnce();
   });
+
+  it('keeps the iCal subscriptions, which exist nowhere else, and drops the rest of the calendar state', () => {
+    const subscription = { id: 's1', url: 'https://example.com/holidays.ics', calendarId: 'c9', name: 'Holidays', color: '#ff0000', refreshInterval: 60, lastRefreshed: null };
+    localStorage.setItem('calendar-storage', JSON.stringify({
+      state: { selectedCalendarIds: ['c1', 'c9'], viewMode: 'week', icalSubscriptions: [subscription] },
+      version: 0,
+    }));
+
+    clearCachedData();
+
+    expect(JSON.parse(localStorage.getItem('calendar-storage')!)).toEqual({ state: { icalSubscriptions: [subscription] }, version: 0 });
+  });
+
+  it('removes calendar state without subscriptions entirely', () => {
+    localStorage.setItem('calendar-storage', JSON.stringify({ state: { viewMode: 'week', icalSubscriptions: [] }, version: 0 }));
+    clearCachedData();
+    expect(localStorage.getItem('calendar-storage')).toBeNull();
+  });
 });

lib/__tests__/jmap-calendar-tasks.test.ts

@@ -1,6 +1,7 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 import { JMAPClient } from '../jmap/client';
 import type { CalendarTask } from '../jmap/types';
+import { jmapErrorType } from '../jmap/jmap-error';
 
 function makeSession() {
   return {
@@ -158,4 +159,15 @@ describe('JMAPClient task operations (#958)', () => {
 
     await expect(client.getCalendarTasks()).rejects.toThrow(/Store unavailable/);
   });
+
+  it('createCalendarTask fails with the error type when the server refuses the whole call', async () => {
+    vi.mocked(globalThis.fetch).mockImplementation(async () => jsonResponse({
+      methodResponses: [['error', { type: 'invalidArguments', description: 'Invalid calendar id' }, '0']],
+    }));
+
+    const error = await client.createCalendarTask({ title: 'New Task' }).then(() => null, (e: unknown) => e);
+    expect(error).toBeInstanceOf(Error);
+    expect((error as Error).message).toContain('Invalid calendar id');
+    expect(jmapErrorType(error)).toBe('invalidArguments');
+  });
 });

lib/clear-cached-data.ts

@@ -16,12 +16,34 @@ const CACHE_STORAGE_KEYS = [
   'calendar-notification-storage',
 ];
 
+/**
+ * The user's iCal subscriptions exist only in the calendar store's persisted
+ * state, next to its caches: keep them and drop the rest.
+ */
+function clearCalendarStorage(storage: Storage): void {
+  let persisted: { state?: { icalSubscriptions?: unknown }; version?: unknown } | null = null;
+  try {
+    persisted = JSON.parse(storage.getItem('calendar-storage') ?? 'null');
+  } catch {
+    /* not ours to read: drop it */
+  }
+  const subscriptions = persisted?.state?.icalSubscriptions;
+  if (!Array.isArray(subscriptions) || subscriptions.length === 0) {
+    storage.removeItem('calendar-storage');
+    return;
+  }
+  storage.setItem('calendar-storage', JSON.stringify({
+    state: { icalSubscriptions: subscriptions },
+    version: persisted?.version ?? 0,
+  }));
+}
+
 /**
  * Clear cached, server-derived data (contacts, calendars, identities, and the
  * in-memory per-account snapshots), then reload so everything is re-fetched
- * fresh for the active account. Accounts and sessions are preserved — this is
- * the non-destructive alternative to the browser's "clear site data", which
- * also wipes the account list.
+ * fresh for the active account. Accounts, sessions and iCal subscriptions are
+ * preserved — this is the non-destructive alternative to the browser's
+ * "clear site data", which also wipes the account list.
  */
 export function clearCachedData(): void {
   // Drop the in-memory per-account store snapshots so a reload can't restore
@@ -36,7 +58,8 @@ export function clearCachedData(): void {
 
   for (const key of CACHE_STORAGE_KEYS) {
     try {
-      window.localStorage.removeItem(key);
+      if (key === 'calendar-storage') clearCalendarStorage(window.localStorage);
+      else window.localStorage.removeItem(key);
     } catch {
       /* ignore storage access errors */
     }

lib/jmap/client.ts

@@ -7953,18 +7953,26 @@ export class JMAPClient implements IJMAPClient {
       }, "0"]
     ], this.calendarUsing());
 
-    const result = response.methodResponses?.[0]?.[1];
+    let result: JMAPResponseResult;
+    try {
+      // A method-level error (unknown calendar, missing capability) means
+      // nothing was created.
+      result = methodResult(response, "0", "CalendarEvent/set");
+    } catch (error) {
+      debug.groupEnd();
+      throw error;
+    }
     debug.log('tasks', 'CalendarTask/create raw set response', result);
 
-    if (result?.notCreated?.["new-task"]) {
+    if (result.notCreated?.["new-task"]) {
       const error = result.notCreated["new-task"];
       debug.warn('tasks', 'CalendarTask/create REJECTED by server', error);
       debug.groupEnd();
-      throw new Error(error.description || "Failed to create task");
+      throw jmapSetError(error.description || "Failed to create task", error);
     }
 
-    const createdId = result?.created?.["new-task"]?.id;
-    const serverCreated = result?.created?.["new-task"];
+    const createdId = result.created?.["new-task"]?.id;
+    const serverCreated = result.created?.["new-task"];
     debug.log('tasks', 'CalendarTask/create server acknowledged', { createdId, serverCreated });
 
     if (!createdId) {

locales/ar/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "جارٍ تحميل التقويمات...",
       "loading_events": "جارٍ تحميل الأحداث...",
       "events_load_failed": "تعذّر تحميل الأحداث. قد لا يكون التقويم محدَّثًا.",
+      "tasks_load_failed": "تعذّر تحميل المهام. قد لا تكون القائمة محدَّثة.",
       "retry": "حاول مرة أخرى"
     },
     "quick_create": {

locales/ca/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Carregant els calendaris...",
       "loading_events": "Carregant els esdeveniments...",
       "events_load_failed": "No s'han pogut carregar els esdeveniments. És possible que el calendari no estigui actualitzat.",
+      "tasks_load_failed": "No s'han pogut carregar les tasques. És possible que la llista no estigui actualitzada.",
       "retry": "Torna-ho a provar"
     },
     "quick_create": {

locales/cs/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Načítání kalendářů...",
       "loading_events": "Načítání událostí...",
       "events_load_failed": "Události se nepodařilo načíst. Kalendář nemusí být aktuální.",
+      "tasks_load_failed": "Úkoly se nepodařilo načíst. Seznam nemusí být aktuální.",
       "retry": "Zkusit znovu"
     },
     "quick_create": {

locales/da/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Indlæser kalendere...",
       "loading_events": "Indlæser begivenheder...",
       "events_load_failed": "Begivenhederne kunne ikke indlæses. Kalenderen er muligvis ikke opdateret.",
+      "tasks_load_failed": "Opgaverne kunne ikke indlæses. Listen er muligvis ikke opdateret.",
       "retry": "Prøv igen"
     },
     "quick_create": {

locales/de/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Kalender werden geladen...",
       "loading_events": "Termine werden geladen...",
       "events_load_failed": "Termine konnten nicht geladen werden. Der Kalender ist möglicherweise nicht aktuell.",
+      "tasks_load_failed": "Aufgaben konnten nicht geladen werden. Die Liste ist möglicherweise nicht aktuell.",
       "retry": "Erneut versuchen"
     },
     "quick_create": {

locales/en/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Loading calendars...",
       "loading_events": "Loading events...",
       "events_load_failed": "Couldn't load events. The calendar may be out of date.",
+      "tasks_load_failed": "Couldn't load tasks. The list may be out of date.",
       "retry": "Try again"
     },
     "quick_create": {

locales/es/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Cargando calendarios...",
       "loading_events": "Cargando eventos...",
       "events_load_failed": "No se pudieron cargar los eventos. Es posible que el calendario no esté actualizado.",
+      "tasks_load_failed": "No se pudieron cargar las tareas. Es posible que la lista no esté actualizada.",
       "retry": "Intentar de nuevo"
     },
     "quick_create": {

locales/fa/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "در حال بارگذاری تقویم‌ها...",
       "loading_events": "در حال بارگذاری رویدادها...",
       "events_load_failed": "بارگذاری رویدادها ممکن نشد. ممکن است تقویم به‌روز نباشد.",
+      "tasks_load_failed": "بارگذاری وظایف ممکن نشد. ممکن است فهرست به‌روز نباشد.",
       "retry": "دوباره تلاش کنید"
     },
     "quick_create": {

locales/fr/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Chargement des calendriers...",
       "loading_events": "Chargement des événements...",
       "events_load_failed": "Impossible de charger les événements. Le calendrier n'est peut-être pas à jour.",
+      "tasks_load_failed": "Impossible de charger les tâches. La liste n'est peut-être pas à jour.",
       "retry": "Réessayer"
     },
     "quick_create": {

locales/he/common.json

@@ -2969,6 +2969,7 @@
       "loading_calendars": "טוען יומנים...",
       "loading_events": "טוען אירועים...",
       "events_load_failed": "לא ניתן לטעון את האירועים. ייתכן שהיומן אינו מעודכן.",
+      "tasks_load_failed": "לא ניתן לטעון את המשימות. ייתכן שהרשימה אינה מעודכנת.",
       "retry": "נסה שוב"
     },
     "quick_create": {

locales/hu/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Naptárak betöltése...",
       "loading_events": "Események betöltése...",
       "events_load_failed": "Nem sikerült betölteni az eseményeket. Előfordulhat, hogy a naptár nem naprakész.",
+      "tasks_load_failed": "Nem sikerült betölteni a feladatokat. Előfordulhat, hogy a lista nem naprakész.",
       "retry": "Próbáld újra"
     },
     "quick_create": {

locales/it/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Caricamento calendari...",
       "loading_events": "Caricamento eventi...",
       "events_load_failed": "Impossibile caricare gli eventi. Il calendario potrebbe non essere aggiornato.",
+      "tasks_load_failed": "Impossibile caricare le attività. L'elenco potrebbe non essere aggiornato.",
       "retry": "Riprova"
     },
     "quick_create": {

locales/ja/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "カレンダーを読み込み中...",
       "loading_events": "予定を読み込み中...",
       "events_load_failed": "予定を読み込めませんでした。カレンダーが最新でない可能性があります。",
+      "tasks_load_failed": "タスクを読み込めませんでした。一覧が最新でない可能性があります。",
       "retry": "再試行"
     },
     "quick_create": {

locales/ko/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "캘린더를 불러오는 중...",
       "loading_events": "일정을 불러오는 중...",
       "events_load_failed": "일정을 불러오지 못했어요. 캘린더가 최신 상태가 아닐 수 있어요.",
+      "tasks_load_failed": "할 일을 불러오지 못했어요. 목록이 최신 상태가 아닐 수 있어요.",
       "retry": "다시 시도"
     },
     "quick_create": {

locales/lv/common.json

@@ -3044,6 +3044,7 @@
       "loading_calendars": "Ielādē kalendārus...",
       "loading_events": "Ielādē pasākumus...",
       "events_load_failed": "Neizdevās ielādēt pasākumus. Kalendārs var nebūt aktuāls.",
+      "tasks_load_failed": "Neizdevās ielādēt uzdevumus. Saraksts var nebūt aktuāls.",
       "retry": "Mēģināt vēlreiz"
     },
     "quick_create": {

locales/mn/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Хуанли ачаалж байна...",
       "loading_events": "Арга хэмжээг ачаалж байна...",
       "events_load_failed": "Арга хэмжээг ачаалж чадсангүй. Хуанли шинэчлэгдээгүй байж магадгүй.",
+      "tasks_load_failed": "Даалгавруудыг ачаалж чадсангүй. Жагсаалт шинэчлэгдээгүй байж магадгүй.",
       "retry": "Дахин оролдоно уу"
     },
     "quick_create": {

locales/nb/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Laster inn kalendere...",
       "loading_events": "Laster inn hendelser...",
       "events_load_failed": "Kunne ikke laste inn hendelser. Kalenderen er kanskje ikke oppdatert.",
+      "tasks_load_failed": "Kunne ikke laste inn oppgaver. Listen er kanskje ikke oppdatert.",
       "retry": "Prøv igjen"
     },
     "quick_create": {

locales/nl/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Agenda's laden...",
       "loading_events": "Evenementen laden...",
       "events_load_failed": "Evenementen konden niet worden geladen. De agenda is mogelijk niet actueel.",
+      "tasks_load_failed": "Taken konden niet worden geladen. De lijst is mogelijk niet actueel.",
       "retry": "Opnieuw proberen"
     },
     "quick_create": {

locales/pl/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Ładowanie kalendarzy...",
       "loading_events": "Ładowanie wydarzeń...",
       "events_load_failed": "Nie udało się wczytać wydarzeń. Kalendarz może być nieaktualny.",
+      "tasks_load_failed": "Nie udało się wczytać zadań. Lista może być nieaktualna.",
       "retry": "Spróbuj ponownie"
     },
     "quick_create": {

locales/pt/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Carregando calendários...",
       "loading_events": "Carregando eventos...",
       "events_load_failed": "Não foi possível carregar os eventos. O calendário pode estar desatualizado.",
+      "tasks_load_failed": "Não foi possível carregar as tarefas. A lista pode estar desatualizada.",
       "retry": "Tentar novamente"
     },
     "quick_create": {

locales/ro/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Se încarcă calendarele...",
       "loading_events": "Se încarcă evenimente...",
       "events_load_failed": "Nu s-au putut încărca evenimentele. Este posibil ca calendarul să nu fie actualizat.",
+      "tasks_load_failed": "Nu s-au putut încărca sarcinile. Este posibil ca lista să nu fie actualizată.",
       "retry": "Încercați din nou"
     },
     "quick_create": {

locales/ru/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Загрузка календарей...",
       "loading_events": "Загрузка событий...",
       "events_load_failed": "Не удалось загрузить события. Календарь может быть неактуален.",
+      "tasks_load_failed": "Не удалось загрузить задачи. Список может быть неактуален.",
       "retry": "Попробовать снова"
     },
     "quick_create": {

locales/sk/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Načítavanie kalendárov...",
       "loading_events": "Načítavanie udalostí...",
       "events_load_failed": "Udalosti sa nepodarilo načítať. Kalendár nemusí byť aktuálny.",
+      "tasks_load_failed": "Úlohy sa nepodarilo načítať. Zoznam nemusí byť aktuálny.",
       "retry": "Skúsiť znova"
     },
     "quick_create": {

locales/tr/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "Takvimler yükleniyor...",
       "loading_events": "Etkinlikler yükleniyor...",
       "events_load_failed": "Etkinlikler yüklenemedi. Takvim güncel olmayabilir.",
+      "tasks_load_failed": "Görevler yüklenemedi. Liste güncel olmayabilir.",
       "retry": "Tekrar dene"
     },
     "quick_create": {

locales/uk/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "Завантаження календарів...",
       "loading_events": "Завантаження подій...",
       "events_load_failed": "Не вдалося завантажити події. Календар може бути неактуальним.",
+      "tasks_load_failed": "Не вдалося завантажити завдання. Список може бути неактуальним.",
       "retry": "Спробуйте знову"
     },
     "quick_create": {

locales/zh-TW/common.json

@@ -3071,6 +3071,7 @@
       "loading_calendars": "正在載入行事曆…",
       "loading_events": "正在載入活動…",
       "events_load_failed": "無法載入活動。行事曆可能不是最新狀態。",
+      "tasks_load_failed": "無法載入工作。清單可能不是最新狀態。",
       "retry": "再試一次"
     },
     "quick_create": {

locales/zh/common.json

@@ -3045,6 +3045,7 @@
       "loading_calendars": "正在加载日历...",
       "loading_events": "正在加载事件...",
       "events_load_failed": "无法加载事件。日历可能不是最新的。",
+      "tasks_load_failed": "无法加载任务。列表可能不是最新的。",
       "retry": "再试一次"
     },
     "quick_create": {

stores/task-store.ts

@@ -5,6 +5,12 @@ import { debug } from '@/lib/debug';
 
 export type TaskViewFilter = 'all' | 'pending' | 'completed' | 'overdue';
 
+/**
+ * The `error` a failed task load leaves. The tasks loaded before stay; the
+ * task list shows a notice for it.
+ */
+export const TASKS_LOAD_ERROR = 'Failed to fetch tasks';
+
 interface TaskStore {
   tasks: CalendarTask[];
   selectedTaskId: string | null;
@@ -52,7 +58,7 @@ export const useTaskStore = create<TaskStore>((set, get) => ({
       set({ tasks, isLoading: false });
     } catch (error) {
       debug.error('TaskStore/fetchTasks failed', error);
-      set({ isLoading: false, error: 'Failed to fetch tasks' });
+      set({ isLoading: false, error: TASKS_LOAD_ERROR });
     }
   },