test(template): add empty fallback coverage (JhaSourav07#3093)

## Description

Fixes JhaSourav07#2863 

Added isolated unit tests for `app/template.tsx` focusing on edge cases,
empty children handling, and fallback rendering stability.

### Changes
- Added `app/template.empty-fallback.test.tsx`
- Mocked `framer-motion` to isolate component behavior
- Verified the template renders successfully with `null` children
- Tested rendering behavior with `undefined` children
- Confirmed empty fragments do not cause runtime or hydration issues
- Verified wrapper structure is preserved when no content is provided
- Tested normal rendering with valid child content
- Improved coverage around empty states and fallback rendering scenarios

## Pillar

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

## Visual Preview

N/A (test-only changes)

## Checklist before requesting a review:

- [x] I have read the `CONTRIBUTING.md` file.
- [x] I have tested these changes locally.
- [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 starred 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 visual changes made).
- [ ] (Recommended) I joined the CommitPulse Discord community for
contributor discussions, mentorship, and faster PR support.

Author: JhaSourav07

app/template.empty-fallback.test.tsx

@@ -0,0 +1,58 @@
+// app/template.empty-fallback.test.tsx
+
+import { describe, expect, it, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import '@testing-library/jest-dom';
+
+vi.mock('framer-motion', () => ({
+  motion: {
+    div: ({ children }: { children?: React.ReactNode }) => (
+      <div data-testid="motion-wrapper">{children}</div>
+    ),
+  },
+}));
+
+import Template from './template';
+
+describe('Template Empty & Missing Input Fallbacks', () => {
+  it('renders successfully with null children', () => {
+    render(<Template>{null}</Template>);
+
+    expect(screen.getByTestId('motion-wrapper')).toBeInTheDocument();
+  });
+
+  it('renders successfully with undefined children', () => {
+    render(<Template>{undefined}</Template>);
+
+    expect(screen.getByTestId('motion-wrapper')).toBeInTheDocument();
+  });
+
+  it('renders successfully with an empty fragment', () => {
+    render(
+      <Template>
+        <></>
+      </Template>
+    );
+
+    expect(screen.getByTestId('motion-wrapper')).toBeInTheDocument();
+  });
+
+  it('preserves wrapper structure when no content is provided', () => {
+    render(<Template>{null}</Template>);
+
+    const wrapper = screen.getByTestId('motion-wrapper');
+
+    expect(wrapper).toBeInTheDocument();
+    expect(wrapper.childElementCount).toBe(0);
+  });
+
+  it('renders provided content correctly', () => {
+    render(
+      <Template>
+        <div>Fallback Content</div>
+      </Template>
+    );
+
+    expect(screen.getByText('Fallback Content')).toBeInTheDocument();
+  });
+});