fix: repair test suite after SWR offline-read changes

Add navigator.onLine guard to SWR refresh IIFEs so background
network calls don't fire in offline mode (prevents fake-IDB leakage
in tests via MSW default handlers).

Fix IDB isolation in affected test files by flushing pending macro
tasks then clearing IDB tables in beforeEach, so stale IDB writes
from previous tests' background IIFEs don't bleed into the next test.

Restore loadBudgetItems and refreshPlaces to apply background refresh
results to store state.

Move tags/categories API calls before the main Promise.all in
loadTrip so MSW handlers resolve during the await window.

client/tests/unit/slices/placesSlice.test.ts

@@ -4,6 +4,7 @@ import { useTripStore } from '../../../src/store/tripStore';
 import { resetAllStores, seedStore } from '../../helpers/store';
 import { buildPlace, buildAssignment } from '../../helpers/factories';
 import { server } from '../../helpers/msw/server';
+import { offlineDb } from '../../../src/db/offlineDb';
 
 vi.mock('../../../src/api/websocket', () => ({
   connect: vi.fn(),
@@ -17,7 +18,9 @@ vi.mock('../../../src/api/websocket', () => ({
   setPreReconnectHook: vi.fn(),
 }));
 
-beforeEach(() => {
+beforeEach(async () => {
+  await new Promise<void>(resolve => setTimeout(resolve, 0));
+  await Promise.all(offlineDb.tables.map(t => t.clear()));
   resetAllStores();
 });