feat: enhance CurrentDutyView with new functionality and improved tests

- Added a button to open the calendar in the no-duty view, triggering the onBack function.
- Implemented tests for the new button functionality and error handling in the CurrentDutyView component.
- Updated localization messages to include the new "Open calendar" label in both English and Russian.
- Refactored layout and styling for better user experience and accessibility.

webapp-next/src/components/current-duty/CurrentDutyView.test.tsx

@@ -57,6 +57,18 @@ describe("CurrentDutyView", () => {
     expect(screen.queryByText(/Back to calendar|Назад к календарю/i)).not.toBeInTheDocument();
   });
 
+  it("shows Open calendar button in no-duty view and it calls onBack", async () => {
+    const onBack = vi.fn();
+    render(<CurrentDutyView onBack={onBack} />);
+    await screen.findByText(/No one is on duty|Сейчас никто не дежурит/i, {}, { timeout: 3000 });
+    const openCalendarBtn = screen.getByRole("button", {
+      name: /Open calendar|Открыть календарь/i,
+    });
+    expect(openCalendarBtn).toBeInTheDocument();
+    fireEvent.click(openCalendarBtn);
+    expect(onBack).toHaveBeenCalled();
+  });
+
   it("shows contact info not set when duty has no phone or username", async () => {
     const { fetchDuties } = await import("@/lib/api");
     const now = new Date();
@@ -81,4 +93,38 @@ describe("CurrentDutyView", () => {
     ).toBeInTheDocument();
     vi.mocked(fetchDuties).mockResolvedValue([]);
   });
+
+  it("shows ends_at line when duty is active", async () => {
+    const { fetchDuties } = await import("@/lib/api");
+    const now = new Date();
+    const start = new Date(now.getTime() - 60 * 60 * 1000);
+    const end = new Date(now.getTime() + 2 * 60 * 60 * 1000);
+    const duty = {
+      id: 1,
+      user_id: 1,
+      start_at: start.toISOString(),
+      end_at: end.toISOString(),
+      event_type: "duty" as const,
+      full_name: "Test User",
+      phone: null,
+      username: null,
+    };
+    vi.mocked(fetchDuties).mockResolvedValue([duty]);
+    render(<CurrentDutyView onBack={vi.fn()} />);
+    await screen.findByText("Test User", {}, { timeout: 3000 });
+    expect(
+      screen.getByText(/Until end of shift at|До конца смены в/i)
+    ).toBeInTheDocument();
+    vi.mocked(fetchDuties).mockResolvedValue([]);
+  });
+
+  it("error state shows Retry as first button", async () => {
+    const { fetchDuties } = await import("@/lib/api");
+    vi.mocked(fetchDuties).mockRejectedValue(new Error("Network error"));
+    render(<CurrentDutyView onBack={vi.fn()} />);
+    await screen.findByText(/Could not load|Не удалось загрузить/i, {}, { timeout: 3000 });
+    const buttons = screen.getAllByRole("button");
+    expect(buttons[0]).toHaveAccessibleName(/Retry|Повторить/i);
+    vi.mocked(fetchDuties).mockResolvedValue([]);
+  });
 });