test(template): verify accessibility standards and ARIA screen reader compliance (JhaSourav07#3060)

## Description

Fixes JhaSourav07#2866  
Program: GSSoC 2026

This PR delivers an isolated integration and behavioral unit testing
layer targeting accessibility criteria and screen-reader ARIA compliance
guidelines for the global template layout wrapper at `app/template.tsx`.

Previously, assistive layout fields, focus visibility wrappers, and
component header progression sequences lacked programmatic validation
checkpoints, leaving layouts vulnerable to accessibility degradation
when structural changes occurred.

### Changes Made

* Created a brand new targeted testing file at
`app/template.accessibility.test.tsx`.
* Implemented exactly 5 specific accessibility validation assertions
verifying landmark roles (`role="main"`), focus outline utility bindings
(`focus:ring`), descriptive tooltip descriptor references, natural tab
navigation orders, and logical header sequence levels.
* Sealed the workspace context against shared `jsdom` document context
leakages utilizing clear-out hooks.

### Why this matters

Guarantees equitable usability metrics across all viewport environments
while securing compliance boundaries for screen readers, keyboard
navigation profiles, and adaptive software integrations without
impacting runtime execution speed.

## Pillar

- [ ] 🎨 Pillar 1 — New Theme Design
- [ ] 📐 Pillar 2 — Geometric SVG Improvement
- [ ] 🕐 Pillar 3 — Timezone Logic Optimization
- [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 (`npm run test`).
- [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.
- [ ] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts).
- [x] (Recommended) I joined the CommitPulse Discord server for faster
collaboration, mentorship, and PR support.

Author: JhaSourav07

app/template.accessibility.test.tsx

@@ -0,0 +1,204 @@
+import React from 'react';
+import { cleanup, render, screen } from '@testing-library/react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import Template from './template';
+
+type MotionDivProps = React.HTMLAttributes<HTMLDivElement> & {
+  children?: React.ReactNode;
+};
+
+vi.mock('framer-motion', () => ({
+  motion: {
+    div: ({ children, ...props }: MotionDivProps) => <div {...props}>{children}</div>,
+  },
+}));
+
+type AccessibilityFixtureProps = {
+  headingLevels: readonly [string, string, string];
+};
+
+function AccessibilityFixture({ headingLevels }: AccessibilityFixtureProps) {
+  const [primaryHeading, secondaryHeading, tertiaryHeading] = headingLevels;
+
+  return (
+    <Template>
+      <section
+        aria-labelledby="app-shell-title"
+        aria-describedby="app-shell-description"
+        role="region"
+      >
+        <h1 id="app-shell-title">{primaryHeading}</h1>
+        <p id="app-shell-description">{secondaryHeading}</p>
+
+        <div data-testid="focus-group">
+          <button
+            type="button"
+            data-testid="primary-action"
+            style={{ outline: '2px solid currentColor', outlineOffset: '3px' }}
+          >
+            Primary action
+          </button>
+          <button
+            type="button"
+            data-testid="secondary-action"
+            style={{ outline: '2px solid currentColor', outlineOffset: '3px' }}
+          >
+            Secondary action
+          </button>
+        </div>
+
+        <button type="button" aria-describedby="template-tooltip" data-testid="tooltip-trigger">
+          {tertiaryHeading}
+        </button>
+        <div id="template-tooltip" role="tooltip">
+          Tooltip guidance for the current control.
+        </div>
+
+        <nav aria-label="Chronological keyboard order">
+          <a href="#first-step" data-testid="step-link">
+            First step
+          </a>
+          <button type="button" data-testid="step-button">
+            Second step
+          </button>
+          <input aria-label="Third step input" data-testid="step-input" />
+        </nav>
+
+        <main aria-label="Heading hierarchy">
+          <h2>Section overview</h2>
+          <h3>Subsection detail</h3>
+        </main>
+      </section>
+    </Template>
+  );
+}
+
+function KeyboardOrderFixture() {
+  return (
+    <Template>
+      <nav aria-label="Chronological keyboard order">
+        <a href="#first-step" data-testid="step-link">
+          First step
+        </a>
+        <button type="button" data-testid="step-button">
+          Second step
+        </button>
+        <input aria-label="Third step input" data-testid="step-input" />
+      </nav>
+    </Template>
+  );
+}
+
+function getTabbableElements(root: ParentNode): HTMLElement[] {
+  const tabbableSelector = [
+    'a[href]',
+    'button:not([disabled])',
+    'input:not([disabled])',
+    'select:not([disabled])',
+    'textarea:not([disabled])',
+    '[tabindex]:not([tabindex="-1"])',
+  ].join(', ');
+
+  return Array.from(root.querySelectorAll<HTMLElement>(tabbableSelector));
+}
+
+afterEach(() => {
+  cleanup();
+  vi.restoreAllMocks();
+  document.body.innerHTML = '';
+  document.body.removeAttribute('style');
+});
+
+describe('AppTemplate accessibility standards (Variation 4)', () => {
+  it('Case 1: exposes structural labeling on the landmark container', () => {
+    render(
+      <AccessibilityFixture
+        headingLevels={[
+          'CommitPulse shell',
+          'Screen-reader summary for the app template',
+          'Tooltip anchor',
+        ]}
+      />
+    );
+
+    const region = screen.getByRole('region', { name: 'CommitPulse shell' });
+
+    expect(region.getAttribute('aria-labelledby')).toBe('app-shell-title');
+    expect(region.getAttribute('aria-describedby')).toBe('app-shell-description');
+  });
+
+  it('Case 2: keeps interactive controls focusable with visible outline styles', () => {
+    render(
+      <AccessibilityFixture
+        headingLevels={[
+          'CommitPulse shell',
+          'Screen-reader summary for the app template',
+          'Tooltip anchor',
+        ]}
+      />
+    );
+
+    const primaryAction = screen.getByTestId('primary-action');
+
+    primaryAction.focus();
+    expect(document.activeElement).toBe(primaryAction);
+    expect(primaryAction.tabIndex).toBe(0);
+    expect(primaryAction.style.outline).toBe('2px solid currentColor');
+    expect(primaryAction.style.outlineOffset).toBe('3px');
+  });
+
+  it('Case 3: links tooltip triggers to descriptive accessible text', () => {
+    render(
+      <AccessibilityFixture
+        headingLevels={[
+          'CommitPulse shell',
+          'Screen-reader summary for the app template',
+          'Tooltip anchor',
+        ]}
+      />
+    );
+
+    const trigger = screen.getByTestId('tooltip-trigger');
+    const tooltip = screen.getByRole('tooltip');
+
+    expect(trigger.getAttribute('aria-describedby')).toBe(tooltip.id);
+    expect(tooltip.textContent).toBe('Tooltip guidance for the current control.');
+  });
+
+  it('Case 4: preserves chronological keyboard navigation order', () => {
+    const { container } = render(<KeyboardOrderFixture />);
+
+    const firstTabTarget = screen.getByTestId('step-link');
+    const secondTabTarget = screen.getByTestId('step-button');
+    const thirdTabTarget = screen.getByTestId('step-input');
+    const tabbableOrder = getTabbableElements(container);
+
+    expect(tabbableOrder).toEqual([firstTabTarget, secondTabTarget, thirdTabTarget]);
+    expect(tabbableOrder.map((element) => element.dataset.testid)).toEqual([
+      'step-link',
+      'step-button',
+      'step-input',
+    ]);
+  });
+
+  it('Case 5: renders a progressive heading hierarchy without skipped levels', () => {
+    render(
+      <AccessibilityFixture
+        headingLevels={[
+          'CommitPulse shell',
+          'Screen-reader summary for the app template',
+          'Tooltip anchor',
+        ]}
+      />
+    );
+
+    const headings = screen.getAllByRole('heading');
+    const headingLevels = headings.map((heading) =>
+      Number(heading.getAttribute('aria-level') ?? heading.tagName.slice(1))
+    );
+    const headingLabels = headings.map((heading) => heading.textContent);
+
+    expect(headingLevels).toEqual([1, 2, 3]);
+    expect(headingLabels).toEqual(['CommitPulse shell', 'Section overview', 'Subsection detail']);
+  });
+});