test(client): expand frontend test suite to 69.1% coverage

Add and extend tests across 32 files (+10 595 lines) covering Admin
panels (AuditLog, Backup, DevNotifications, GitHub), Collab (Chat,
Notes, Panel, Polls), Planner (DayDetailPanel, DayPlanSidebar),
Settings (DisplaySettings, Integrations, MapSettings), Files
(FileManager, FilesPage), Map, Layout (DemoBanner,
InAppNotificationBell), shared pickers (CustomDateTimePicker,
CustomTimePicker), Vacay holidays, pages (Dashboard, Login), unit
stores (authStore, inAppNotificationStore), API (authUrl, client
integration), and i18n. Also updates sonar-project.properties and
MSW trip handlers to support the new cases.

client/tests/helpers/msw/handlers/trips.ts

@@ -46,4 +46,14 @@ export const tripsHandlers = [
   http.get('/api/trips/:id/accommodations', () => {
     return HttpResponse.json({ accommodations: [] });
   }),
+
+  http.delete('/api/trips/:id', () => {
+    return HttpResponse.json({ success: true });
+  }),
+
+  http.post('/api/trips/:id/copy', async ({ params, request }) => {
+    const body = await request.json() as Record<string, unknown>;
+    const trip = buildTrip({ id: Number(params.id) + 1000, ...body });
+    return HttpResponse.json({ trip });
+  }),
 ];