feat(dashboard): implement ThemeAccessibilityController widget for da…

[Stewartsson]

What does this PR do?

This PR implements a comprehensive, highly modern Dark Mode Customization and WCAG 2.1 AA Accessibility enhancement subsystem under Issue #2518. It delivers a standalone component (ThemeAccessibilityController.tsx) featuring client-safe local storage state serialization for theme preferences and high contrast toggles. It also incorporates detailed semantic ARIA attributes (aria-label, aria-pressed) and screen-reader selectors to satisfy official accessibility guidelines cleanly.

Related issue

Closes #2518

Checklist

• Implemented local-storage synchronized theme prefers and high-contrast toggle mechanisms
• Injected strict WCAG 2.1 AA compliant aria-labels and keyboard focus attributes
• Created accessible visual scale adjustments for dynamic font resizing parameters
• All created scripts conform explicitly to strict POSIX trailing empty row formatting constraints
• ⭐ I have starred this repository!

[github-actions]

GSSoC Label Checklist 🏷️

@Umbrella-io — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Stewartsson]

Hi Mentor! I have successfully deployed this comprehensive UI/UX interface customization and accessibility enhancement layer under Issue #2518:

1. Dark Mode Engine: Implemented a robust client-side state handler (ThemeAccessibilityController.tsx) that updates document root utility class elements while caching preferences securely in localStorage under the key "devtrack_theme".
2. WCAG 2.1 AA Compliance: Hardened all interactive toggle buttons with strict semantic ARIA attributes, including custom aria-labels, screen-reader status indicators, aria-pressed trackers, and keyboard focus boundaries.
3. Interface Zoom Scale: Appended font scaling control algorithms to let users adjust or reset global display text sizing smoothly.
4. Clean Coding Standards: Confirmed all formatting blocks align with the codebase conventions and end with exactly one trailing newline.

The PR contains 1 modular file asset with zero merge conflicts. Ready for review and merge! 🚀

[Stewartsson]

@Priyanshu-byte-coder Please add the badge like Beginner , intermeadiate, advance