fix(schedule): stop the whole agenda from unmounting on every calendar refetch

frontend/src/features/schedule/presentation/useScheduleCalendar.ts

@@ -57,6 +57,22 @@ export function useScheduleCalendar(
   const [locationsLoading, setLocationsLoading] = useState(true);
   const [occurrencesError, setOccurrencesError] = useState<string | null>(null);
   const [locationsError, setLocationsError] = useState<string | null>(null);
+  // 首次加载成功后，后续重取（增删日程/语音写日程/轮询）不再把整个 agenda
+  // 卸载重挂——只在真的还没数据时才盖全屏转圈，之后都是后台悄悄换数据。必须等
+  // 两个请求都没报错才算数：首次加载失败时不能锁上，否则点重试会在空/旧数据
+  // 上直接显示 agenda，而不是原来的全屏首次加载态。渲染期间同步翻它，不放进
+  // useEffect（react-hooks 规则不允许在 effect 里直接 setState 触发级联渲染，
+  // 也不允许在渲染期间读 ref）。
+  const [initialLoadDone, setInitialLoadDone] = useState(false);
+  if (
+    !initialLoadDone &&
+    !occurrencesLoading &&
+    !locationsLoading &&
+    occurrencesError === null &&
+    locationsError === null
+  ) {
+    setInitialLoadDone(true);
+  }
   const [reloadToken, setReloadToken] = useState(0);
 
   const focusKey = focusTarget
@@ -215,7 +231,7 @@ export function useScheduleCalendar(
     occurrencesByDate,
     selectedOccurrences,
     locationSchedules,
-    loading: occurrencesLoading || locationsLoading,
+    loading: !initialLoadDone && (occurrencesLoading || locationsLoading),
     error: occurrencesError ?? locationsError,
     selectDate,
     changeMonth,

frontend/tests/unit/features/schedule/presentation/useScheduleCalendar.test.ts

@@ -300,4 +300,87 @@ describe('useScheduleCalendar', () => {
     expect(result.current.locationSchedules).toHaveLength(1);
     expect(getLocationSchedules).toHaveBeenCalledTimes(1);
   });
+
+  it('keeps loading false on a background refetch after the first load completes', async () => {
+    let resolveSecondFetch: (value: readonly []) => void = () => {};
+    const getSchedulesByRange = jest
+      .fn<ScheduleCalendarReadService['getSchedulesByRange']>()
+      .mockResolvedValueOnce([])
+      .mockImplementationOnce(
+        () =>
+          new Promise((resolve) => {
+            resolveSecondFetch = resolve;
+          }),
+      );
+    const service = {
+      getSchedulesByRange,
+      getSchedulesByDay: jest.fn(),
+      getLocationSchedules: jest
+        .fn<ScheduleCalendarReadService['getLocationSchedules']>()
+        .mockResolvedValue([]),
+    } as ScheduleCalendarReadService;
+
+    const { result } = renderHook(() =>
+      useScheduleCalendar(service, 'account-a', 'Asia/Shanghai', new Date(2026, 7, 14)),
+    );
+
+    await waitFor(() => expect(result.current.loading).toBe(false));
+    expect(getSchedulesByRange).toHaveBeenCalledTimes(1);
+
+    act(() => {
+      result.current.retry();
+    });
+    await act(async () => {
+      await Promise.resolve();
+    });
+
+    expect(getSchedulesByRange).toHaveBeenCalledTimes(2);
+    expect(result.current.loading).toBe(false);
+
+    await act(async () => {
+      resolveSecondFetch([]);
+    });
+  });
+
+  it('keeps the full-screen loading state on retry after the initial load fails', async () => {
+    let resolveRetryFetch: (value: readonly []) => void = () => {};
+    const getSchedulesByRange = jest
+      .fn<ScheduleCalendarReadService['getSchedulesByRange']>()
+      .mockRejectedValueOnce(new Error('network error'))
+      .mockImplementationOnce(
+        () =>
+          new Promise((resolve) => {
+            resolveRetryFetch = resolve;
+          }),
+      );
+    const service = {
+      getSchedulesByRange,
+      getSchedulesByDay: jest.fn(),
+      getLocationSchedules: jest
+        .fn<ScheduleCalendarReadService['getLocationSchedules']>()
+        .mockResolvedValue([]),
+    } as ScheduleCalendarReadService;
+
+    const { result } = renderHook(() =>
+      useScheduleCalendar(service, 'account-a', 'Asia/Shanghai', new Date(2026, 7, 14)),
+    );
+
+    await waitFor(() => expect(result.current.error).not.toBeNull());
+    expect(result.current.loading).toBe(false);
+
+    act(() => {
+      result.current.retry();
+    });
+    await act(async () => {
+      await Promise.resolve();
+    });
+
+    expect(getSchedulesByRange).toHaveBeenCalledTimes(2);
+    expect(result.current.loading).toBe(true);
+
+    await act(async () => {
+      resolveRetryFetch([]);
+    });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+  });
 });