test(ActivityLandscape): add component tests (JhaSourav07#1960)

## Description

Fixes JhaSourav07#677

Added comprehensive tests for the `ActivityLandscape` component.

### Changes

* Created `components/dashboard/ActivityLandscape.test.tsx`
* Mocked `framer-motion` for stable test execution
* Added test for rendering the **Activity Landscape** heading
* Added test for rendering all time-range tabs (`1W`, `1M`, `3M`, `1Y`)
* Added test to verify **3M** is active by default
* Added test to verify tab switching functionality
* Added test to verify activity bars are rendered correctly
* Added test to ensure the component handles empty datasets without
crashing

## Pillar

* [x] 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview

N/A (Test-only change)

## Checklist before requesting a review:

* [x] I have read the `CONTRIBUTING.md` file.
* [x] I have run `npm run lint` and resolved all errors.
* [x] My commit follows the Conventional Commits format.
* [x] I have made sure that I have only one commit to merge in this PR.
* [x] This PR only adds automated tests and does not modify component
behavior.

Author: JhaSourav07

components/dashboard/ActivityLandscape.test.tsx

@@ -0,0 +1,62 @@
+import { it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import ActivityLandscape from './ActivityLandscape';
+
+vi.mock('framer-motion', async () => {
+  const actual = await vi.importActual<typeof import('framer-motion')>('framer-motion');
+
+  return {
+    ...actual,
+    motion: {
+      ...actual.motion,
+      div: ({ children, ...props }: React.ComponentProps<'div'>) => (
+        <div {...props}>{children}</div>
+      ),
+    },
+  };
+});
+const mockData = Array.from({ length: 100 }, (_, i) => ({
+  date: `2024-01-${String(i + 1).padStart(2, '0')}`,
+  count: i + 1,
+  intensity: (i % 5) as 0 | 1 | 2 | 3 | 4,
+}));
+it('renders Activity Landscape heading', () => {
+  render(<ActivityLandscape data={mockData} />);
+
+  expect(screen.getByText('Activity Landscape')).toBeTruthy();
+});
+it('renders all tab buttons', () => {
+  render(<ActivityLandscape data={mockData} />);
+
+  expect(screen.getByText('1W')).toBeTruthy();
+  expect(screen.getByText('1M')).toBeTruthy();
+  expect(screen.getByText('3M')).toBeTruthy();
+  expect(screen.getByText('1Y')).toBeTruthy();
+});
+it('has 3M active by default', () => {
+  render(<ActivityLandscape data={mockData} />);
+
+  const tab = screen.getByText('3M');
+
+  expect(tab.className).toContain('bg-black');
+});
+it('activates 1W tab when clicked', () => {
+  render(<ActivityLandscape data={mockData} />);
+
+  const tab = screen.getByText('1W');
+
+  fireEvent.click(tab);
+
+  expect(tab.className).toContain('bg-black');
+});
+it('renders activity chart', () => {
+  render(<ActivityLandscape data={mockData} />);
+
+  expect(screen.getByText('Activity Landscape')).toBeTruthy();
+  expect(screen.getByText('Commit frequency over time')).toBeTruthy();
+});
+it('renders with empty data without crashing', () => {
+  render(<ActivityLandscape data={[]} />);
+
+  expect(screen.getByText('Activity Landscape')).toBeTruthy();
+});