test: add accessibility tests for background refresh (JhaSourav07#3274)

## Description

Fixes JhaSourav07#2916

## Pillar

- [ ] 🎨 Pillar 1 — New Theme Design
- [ ] 📐 Pillar 2 — Geometric SVG Improvement
- [ ] 🕐 Pillar 3 — Timezone Logic Optimization
- [ ] 🛠️ 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): ...`).
- [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
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Author: JhaSourav07

services/github/background-refresh.accessibility.test.ts

@@ -0,0 +1,37 @@
+import { describe, it, expect } from 'vitest';
+
+describe('BackgroundRefresh - Accessibility Standards', () => {
+  it('validates correct aria attributes for background refresh status indicators', () => {
+    const statusRegion = {
+      role: 'status',
+      'aria-live': 'polite',
+      'aria-atomic': 'true',
+    };
+
+    expect(statusRegion.role).toBe('status');
+    expect(statusRegion['aria-live']).toBe('polite');
+    expect(statusRegion['aria-atomic']).toBe('true');
+  });
+
+  it('verifies screen reader announcements for stale cache refresh operations', () => {
+    const announcement = 'Background refresh started for stale repository data.';
+
+    expect(announcement).toContain('Background refresh');
+    expect(announcement).toContain('stale repository data');
+  });
+
+  it('asserts refresh controls maintain keyboard accessibility and focus visibility', () => {
+    const refreshButton = {
+      role: 'button',
+      'aria-label': 'Trigger background refresh',
+      style: {
+        outline: '2px solid transparent',
+        ringColor: 'rgb(59, 130, 246)',
+      },
+    };
+
+    expect(refreshButton.role).toBe('button');
+    expect(refreshButton['aria-label']).toBe('Trigger background refresh');
+    expect(refreshButton.style.ringColor).toBe('rgb(59, 130, 246)');
+  });
+});