feat: add multilingual support and accessibility controls

[nivaslinga2]

📝 PR Description

This PR adds multilingual localization and a smart accessibility panel to the ReGenX dashboard.

Included changes

• Added a language selector in the top navigation with support for English, Hindi, Telugu, and German.
• Added src/i18n.js to handle UI text translation for labels, placeholders, buttons, and selected dynamic content.
• Added src/accessibility.js to provide:
  • Text-to-speech support
  • Font zoom controls
  • High-contrast mode
  • Dyslexic-friendly font mode
  • Reduced-motion mode
• Integrated the accessibility manager into src/app.js.
• Updated service-worker.js to cache the new accessibility and i18n assets and bumped the cache version.
• Updated styles in src/styles.css and UI hooks in index.html.

Why this matters

These changes improve usability for multilingual users and make the dashboard more accessible for users with visual, reading, or motion-sensitivity needs.

🎯 GSSoC Points Target

• Difficulty: level:critical
• Quality: quality:exceptional
• Labels Requested: gssoc:approved, level:critical, quality:exceptional

💎 Quality Checklist

• Added multilingual switcher to the dashboard UI
• Added accessibility control panel
• Updated service worker cache entries
• Integrated new modules into the app
• Updated styles for both features

📸 Screenshots / Video

🧪 Testing Done

• Verified the language selector appears in the topbar.
• Verified accessibility panel opens and toggles options.
• Verified new files are included in service worker static assets.
• Verified app integration through updated index.html and src/app.js.

[nivaslinga2]

Hi @Shruti070107 , this PR is related to issue #169. Please review it when you get time and finalize the changes.

[Shruti070107]

This branch has conflicts that must be resolved

[nivaslinga2]

Hi @Shruti070107, PR is now updated and has no conflicts.