test: add dual-parameter support and sync mocks for import/export tests

Update test infrastructure to support the dual app type parameter pattern
(app_type enum + app string) introduced in 590be4e:

- Add toast.warning mock for partial-success status handling
- Add syncCurrentProvidersLive mock to test post-import sync behavior
- Update MSW handlers to accept both app_type and app parameters with
  fallback resolution (app ?? app_type) across 7 provider endpoints
- Add sync_current_providers_live endpoint mock returning success

This ensures test compatibility during the app_type → app parameter
migration and enables testing of the new partial-success import flow.

tests/hooks/useImportExport.test.tsx

@@ -4,11 +4,13 @@ import { useImportExport } from "@/hooks/useImportExport";
 
 const toastSuccessMock = vi.fn();
 const toastErrorMock = vi.fn();
+const toastWarningMock = vi.fn();
 
 vi.mock("sonner", () => ({
   toast: {
     success: (...args: unknown[]) => toastSuccessMock(...args),
     error: (...args: unknown[]) => toastErrorMock(...args),
+    warning: (...args: unknown[]) => toastWarningMock(...args),
   },
 }));
 
@@ -16,6 +18,7 @@ const openFileDialogMock = vi.fn();
 const importConfigMock = vi.fn();
 const saveFileDialogMock = vi.fn();
 const exportConfigMock = vi.fn();
+const syncCurrentProvidersLiveMock = vi.fn();
 
 vi.mock("@/lib/api", () => ({
   settingsApi: {
@@ -23,6 +26,7 @@ vi.mock("@/lib/api", () => ({
     importConfigFromFile: (...args: unknown[]) => importConfigMock(...args),
     saveFileDialog: (...args: unknown[]) => saveFileDialogMock(...args),
     exportConfigToFile: (...args: unknown[]) => exportConfigMock(...args),
+    syncCurrentProvidersLive: (...args: unknown[]) => syncCurrentProvidersLiveMock(...args),
   },
 }));
 
@@ -33,6 +37,8 @@ beforeEach(() => {
   exportConfigMock.mockReset();
   toastSuccessMock.mockReset();
   toastErrorMock.mockReset();
+  toastWarningMock.mockReset();
+  syncCurrentProvidersLiveMock.mockReset();
   vi.useFakeTimers();
 });