test(VisualizationTooltip): add unit tests for tooltip rendering and positioning (JhaSourav07#3042)

## Description
Adds a dedicated test suite for `VisualizationTooltip` covering its core
rendering and positioning behavior.

## Changes

- Added `components/dashboard/VisualizationTooltip.test.tsx`
- Verified tooltip renders with `role="tooltip"`
- Verified title is displayed correctly
- Verified children content is rendered
- Verified custom `x` and `y` coordinates are applied to tooltip styles
- Verified nested React elements are rendered properly
- Mocked `framer-motion` to isolate component behavior during testing

Fixes JhaSourav07#2277 

## Pillar

- [x] 🎨 Pillar 1 — New Theme Design
- [x] 📐 Pillar 2 — Geometric SVG Improvement
- [x] 🛠️ Other (Bug fix, refactoring, docs)


## Checklist before requesting a review:

- [x] I have read the `CONTRIBUTING.md` file.
- [x] I have tested these changes locally
(`localhost:3000/api/streak?user=YOUR_USERNAME`).
- [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors (CI will fail otherwise).
- [x] My commits follow the Conventional Commits format (e.g.,
`feat(themes): ...`, `fix(calculate): ...`).
- [x] I have updated `README.md` if I added a new theme or URL
parameter.
- [x] I have started the repo.
- [x] I have made sure that i have only one commit to merge in this PR.
- [x] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts).
- [x] (Recommended) I joined the CommitPulse Discord community for
contributor discussions, mentorship, and faster PR support.

Author: JhaSourav07

components/dashboard/VisualizationTooltip.test.tsx

@@ -0,0 +1,76 @@
+// components/dashboard/VisualizationTooltip.test.tsx
+import { render, screen } from '@testing-library/react';
+import { describe, expect, it, vi } from 'vitest';
+import type { HTMLAttributes, ReactNode } from 'react';
+import VisualizationTooltip from './VisualizationTooltip';
+import '@testing-library/jest-dom/vitest';
+
+// framer-motion mock
+vi.mock('framer-motion', () => ({
+  motion: {
+    div: ({ children, ...props }: HTMLAttributes<HTMLDivElement> & { children?: ReactNode }) => (
+      <div {...props}>{children}</div>
+    ),
+  },
+}));
+
+describe('VisualizationTooltip', () => {
+  it('renders tooltip role', () => {
+    render(
+      <VisualizationTooltip title="Tooltip Title" x={100} y={200}>
+        Content
+      </VisualizationTooltip>
+    );
+
+    expect(screen.getByRole('tooltip')).toBeInTheDocument();
+  });
+
+  it('renders title correctly', () => {
+    render(
+      <VisualizationTooltip title="Commits" x={100} y={200}>
+        Content
+      </VisualizationTooltip>
+    );
+
+    expect(screen.getByText('Commits')).toBeInTheDocument();
+  });
+
+  it('renders children content', () => {
+    render(
+      <VisualizationTooltip title="Title" x={100} y={200}>
+        <span>5 contributions</span>
+      </VisualizationTooltip>
+    );
+
+    expect(screen.getByText('5 contributions')).toBeInTheDocument();
+  });
+
+  it('applies x and y coordinates to style', () => {
+    render(
+      <VisualizationTooltip title="Title" x={150} y={250}>
+        Content
+      </VisualizationTooltip>
+    );
+
+    const tooltip = screen.getByRole('tooltip');
+
+    expect(tooltip).toHaveStyle({
+      left: '150px',
+      top: '250px',
+    });
+  });
+
+  it('renders nested React elements passed as children', () => {
+    render(
+      <VisualizationTooltip title="Stats" x={10} y={20}>
+        <>
+          <div>Total: 10</div>
+          <div>Today: 2</div>
+        </>
+      </VisualizationTooltip>
+    );
+
+    expect(screen.getByText('Total: 10')).toBeInTheDocument();
+    expect(screen.getByText('Today: 2')).toBeInTheDocument();
+  });
+});