test(portal-behandel): a refresh must clear a stale load failure (refs #162)

If the first read fails the werkbak shows its error until the behandelaar
reloads — the very thing this slice removes. Fails with "expected <p
utrecht-paragraph …> to be null".

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/behandel/src/app/werkbak/werkbak-page.spec.ts

@@ -145,6 +145,30 @@ describe('WerkbakPage', () => {
     }
   });
 
+  it('clears a load failure once a refresh succeeds', async () => {
+    // Without this the werkbak stays stuck on the error until the behandelaar reloads — the very
+    // thing this slice removes. A recovered read must put the rows back.
+    vi.useFakeTimers();
+    try {
+      const getBehandelWerkbak = vi
+        .fn()
+        .mockReturnValueOnce(throwError(() => new Error('503')))
+        .mockReturnValue(of(sample));
+      const { providers } = setup({ getBehandelWerkbak });
+      const { detectChanges } = await render(WerkbakPage, { providers });
+
+      expect(screen.getByText(/kon de werkbak niet laden/i)).toBeTruthy();
+
+      vi.advanceTimersByTime(WERKBAK_REFRESH_MS);
+      detectChanges();
+
+      expect(screen.queryByText(/kon de werkbak niet laden/i)).toBeNull();
+      expect(screen.getByText('reg-1')).toBeTruthy();
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
   it('shows an empty state when the werkbak has no items', async () => {
     const { providers } = setup({ getBehandelWerkbak: vi.fn().mockReturnValue(of([])) });
     await render(WerkbakPage, { providers });