fix(appointments): detail page back/breadcrumb return to the appointment day

AppointmentDetailPage now derives the appointment's local day from slot_start
and points both the «بازگشت» button and the «نوبت‌ها» breadcrumb to
/admin/appointments?date=<that day>, so viewing/acting on an appointment from
any day returns to that day instead of today.

Test: the «نوبت‌ها» breadcrumb links back to the appointment's date.

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

assets/admin/pages/AppointmentDetailPage.test.tsx

@@ -0,0 +1,43 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { screen, waitFor } from '@testing-library/react';
+import { Routes, Route } from 'react-router-dom';
+import { renderWithProviders } from '../test/utils';
+
+vi.mock('../lib/api', () => ({
+  api: { get: vi.fn(), post: vi.fn(), patch: vi.fn(), put: vi.fn(), delete: vi.fn() },
+  ApiError: class extends Error {},
+}));
+
+import { api } from '../lib/api';
+import AppointmentDetailPage from './AppointmentDetailPage';
+
+const get = api.get as ReturnType<typeof vi.fn>;
+// 2024-06-01 12:00 محلی
+const slotStart = Math.floor(new Date('2024-06-01T12:00:00').getTime() / 1000);
+
+beforeEach(() => {
+  get.mockReset();
+  get.mockResolvedValue({
+    success: true,
+    data: {
+      uuid: 'ap1', patient_name: 'ساغر', patient_mobile: '09120000000',
+      slot_start: slotStart, slot_end: slotStart + 1800, status: 'confirmed', version: 1, created_at: slotStart,
+    },
+  });
+});
+
+describe('AppointmentDetailPage — بازگشت به همان روز', () => {
+  it('the «نوبت‌ها» breadcrumb points back to the appointment day', async () => {
+    renderWithProviders(
+      <Routes>
+        <Route path="/admin/appointments/:uuid" element={<AppointmentDetailPage />} />
+      </Routes>,
+      { route: '/admin/appointments/ap1' },
+    );
+    // پس از بارگذاری نوبت، لینک «نوبت‌ها» باید به روزِ نوبت اشاره کند
+    await waitFor(() => {
+      const link = screen.getByText('نوبت‌ها').closest('a');
+      expect(link?.getAttribute('href')).toContain('date=2024-06-01');
+    });
+  });
+});