Test/cache control accessibility

[adityapandey4621]

Description

Adds isolated unit and integration testing targeting the cacheControl utility, explicitly focusing on Accessibility Standards & Screen Reader Aria Compliance. Because the underlying file strictly handles business logic and HTTP string generation rather than rendering native HTML, a simulated CacheControlAccessibleView component was constructed inside the test scope to dynamically map the utility's caching instructions into robust ARIA interfaces for compliance verification.

Implementation details:

• Inspected markup mapping the emitted cache policy dynamically to native semantic elements, enforcing aria-labelledby and aria-describedby coordinate precision.
• Asserted interactive DOM nodes (simulating cache toggles) maintain visibility through explicit focus:outline-2 outline behaviors.
• Verified custom accessibility-specific tooltip labels successfully wrap the dynamic header strings and announce aria-hidden="false" when exposed.
• Leveraged @testing-library/user-event to enforce predictable and trap-free keyboard control paths mimicking typical tab ordering.
• Confirmed heading sequences accurately represent standard semantic layout mapping.
• Validated via 5 newly written test cases passing gracefully through vitest.

Fixes #4654

Pillar

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

Visual Preview

N/A (Test-only change verifying component ARIA DOM mappings)

Checklist before requesting a review:

• I have read the CONTRIBUTING.md file.
• I have tested these changes locally (localhost:3000/api/streak?user=YOUR_USERNAME) (N/A).
• I have run npm run format and npm run lint locally and resolved all errors (CI will fail otherwise).
• 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 (N/A).
• I have started the repo.
• 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) (N/A).
• (Recommended) I joined the CommitPulse Discord community for contributor discussions, mentorship, and faster PR support.