Add durable toasts with an inline action button

src/app/components/Toaster.test.tsx

@@ -171,6 +171,45 @@ describe('Toaster exit animation (two-phase dismiss)', () => {
     vi.useRealTimers();
   });
 
+  test('a durable toast does not auto-dismiss, and its action runs then dismisses it', () => {
+    vi.useFakeTimers();
+    const onClick = vi.fn();
+    let id: string;
+    act(() => {
+      id = useNotificationStore.getState().notify({
+        kind: 'info',
+        title: 'Update available',
+        message: 'A new version is ready.',
+        durable: true,
+        action: { label: 'Reload', onClick },
+      });
+      root.render(<Toaster />);
+    });
+
+    // Well past the auto-dismiss window — still present (durable).
+    act(() => {
+      vi.advanceTimersByTime(60000);
+    });
+    expect(useNotificationStore.getState().notifications.some((n) => n.id === id!)).toBe(true);
+
+    // The action button runs the handler, then the toast exits.
+    const actionBtn = Array.from(container.querySelectorAll('button')).find(
+      (b) => b.textContent === 'Reload',
+    );
+    expect(actionBtn).toBeTruthy();
+    act(() => {
+      actionBtn!.dispatchEvent(new MouseEvent('click', { bubbles: true }));
+    });
+    expect(onClick).toHaveBeenCalledTimes(1);
+
+    act(() => {
+      vi.advanceTimersByTime(TOAST_EXIT_MS);
+    });
+    expect(useNotificationStore.getState().notifications.some((n) => n.id === id!)).toBe(false);
+
+    vi.useRealTimers();
+  });
+
   test('clicking close twice does not reset the exit timer', () => {
     vi.useFakeTimers();
     let id: string;