test(ui): add responsive rendering tests for ComparisonStatsCard (JhaSourav07#1663)

## Description
Adds a new test suite `ComparisonStatsCard responsive rendering and
growth trends (Variation 3)` to
`components/dashboard/ComparisonStatsCard.test.tsx` verifying
positive/negative growth indicators, winner badges, zero values, and
large values render correctly.

Fixes JhaSourav07#1530

## Pillar
- [x] 🛠️ Other (Bug fix, refactoring, docs)

## Checklist before requesting a review:
- [x] I have read the `CONTRIBUTING.md` file.
- [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors.
- [x] My commits follow the Conventional Commits format.
- [x] I have made sure that i have only one commit to merge in this PR.

Author: JhaSourav07

components/dashboard/ComparisonStatsCard.test.tsx

@@ -146,3 +146,82 @@ describe('ComparisonStatsCard', () => {
     expect(screen.queryByText('Winner')).toBeNull();
   });
 });
+
+describe('ComparisonStatsCard responsive rendering and growth trends (Variation 3)', () => {
+  it('renders positive growth trend with winner badge for higher value', () => {
+    render(
+      <ComparisonStatsCard
+        title="Streak"
+        valueA={120}
+        valueB={40}
+        labelA="Alice"
+        labelB="Bob"
+        icon="Flame"
+      />
+    );
+    expect(screen.getByText('Winner')).toBeDefined();
+    expect(screen.getByText('120')).toBeDefined();
+    expect(screen.getByText('40')).toBeDefined();
+  });
+
+  it('renders negative growth indicator — no winner badge for lower value', () => {
+    render(
+      <ComparisonStatsCard
+        title="Streak"
+        valueA={20}
+        valueB={80}
+        labelA="Alice"
+        labelB="Bob"
+        icon="Flame"
+      />
+    );
+    const winners = screen.getAllByText('Winner');
+    expect(winners.length).toBe(1);
+    expect(screen.getByText('20').className).not.toMatch(/emerald/);
+  });
+
+  it('renders title and icon correctly', () => {
+    render(
+      <ComparisonStatsCard
+        title="Pull Requests"
+        valueA={10}
+        valueB={5}
+        labelA="Dev A"
+        labelB="Dev B"
+        icon="GitBranch"
+      />
+    );
+    expect(screen.getByText(/Pull Requests/i)).toBeDefined();
+    expect(screen.getByText('Dev A')).toBeDefined();
+    expect(screen.getByText('Dev B')).toBeDefined();
+  });
+
+  it('renders zero values without crashing', () => {
+    render(
+      <ComparisonStatsCard
+        title="Commits"
+        valueA={0}
+        valueB={0}
+        labelA="Alice"
+        labelB="Bob"
+        icon="GitCommit"
+      />
+    );
+    expect(screen.queryByText('Winner')).toBeNull();
+  });
+
+  it('renders large values correctly', () => {
+    render(
+      <ComparisonStatsCard
+        title="Total Contributions"
+        valueA={9999}
+        valueB={1}
+        labelA="Alice"
+        labelB="Bob"
+        icon="TrendingUp"
+      />
+    );
+    expect(screen.getByText('9999')).toBeDefined();
+    expect(screen.getByText('Winner')).toBeDefined();
+  });
+});