test(ui): improve ThemeQuickPresets responsive rendering coverage (JhaSourav07#2025)

## Description

Fixes JhaSourav07#1543 
## Changes Made

- Added rerender coverage for `ThemeQuickPresets`
- Verified accessible theme controls remain visible after rerender
- Added accessibility assertions for rendered theme buttons
- Improved responsive rendering test coverage for theme preset controls

## Testing

- Ran targeted Vitest suite:
  - `npx vitest components/dashboard/ThemeSelector.test.tsx`

All tests passed successfully.
## Pillar

- [ ] 🎨 Pillar 1 — New Theme Design
- [ ] 📐 Pillar 2 — Geometric SVG Improvement
- [ ] 🕐 Pillar 3 — Timezone Logic Optimization
- [x] 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview

## 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): ...`).
- [] 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/ThemeSelector.test.tsx

@@ -66,4 +66,22 @@ describe('ThemeSelector (ThemeQuickPresets)', () => {
     expect(screen.getByLabelText(/apply dracula theme/i)).toBeInTheDocument();
     expect(screen.getByLabelText(/apply neon theme/i)).toBeInTheDocument();
   });
+  it('renders accessible theme controls consistently after rerender', () => {
+    const { rerender } = render(
+      <ThemeQuickPresets theme="dracula" onThemeChange={mockOnThemeChange} />
+    );
+
+    rerender(<ThemeQuickPresets theme="neon" onThemeChange={mockOnThemeChange} />);
+
+    const buttons = screen.getAllByRole('button');
+
+    expect(buttons.length).toBeGreaterThanOrEqual(2);
+
+    buttons.forEach((button) => {
+      expect(button).toBeVisible();
+      expect(button).toHaveAccessibleName();
+    });
+
+    expect(screen.getByLabelText(/apply neon theme/i)).toBeInTheDocument();
+  });
 });