feat(web): enforce keyboard focus trapping in custom modals(closes #2090)

[shauryavardhan1307]

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📋 PR Summary & Link

• Closes [Accessibility] Enforce Focus Trap in custom Modals #2090
• Summary: Implemented keyboard focus trapping inside custom modals (ExpiryModal and ExportModal) to meet WCAG accessibility standards for dialogs. Added a reusable custom React hook useFocusTrap to handle focus cycle and restoration without external package dependencies.

📸 Proof of Work (Screenshots / Logs)

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• Frontend/UI changes: You MUST attach screenshots or screen recordings (GIFs/Videos) showing the UI changes.

Note: This is an accessibility behavior change for keyboard navigation (focus trapping/restoration) with no visual UI style changes. Programmatic verification logs are attached below:

Unit Test Execution Logs

PASS tests/useFocusTrap.test.tsx
  useFocusTrap
    √ automatically focuses the first focusable element inside the ref container on mount when enabled (50 ms)
    √ traps Tab key so that pressing Tab on the last element wraps focus back to the first (13 ms)
    √ traps Shift+Tab key so that pressing Shift+Tab on the first element wraps focus to the last (7 ms)
    √ restores focus to the previously focused element when unmounted (6 ms)

Test Suites: 1 passed, 1 total
Tests:       4 passed, 4 total
Snapshots:   0 total
Time:        1.562 s
Ran all test suites matching tests/useFocusTrap.test.tsx.

🏷️ PR Type

• 🐛 type: bug
• ✨ type: feature
• 📖 type: docs
• 🧪 type: testing
• 🔒 type: security
• ⚡ type: performance
• 🎨 type: design
• ♻️ type: refactor
• 🛠️ type: devops
• ♿ type: accessibility

✅ Checklist

• My PR has a linked issue (Closes #2090)
• I have pulled the latest main and resolved any conflicts

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[github-actions]

🎉 Congratulations @shauryavardhan1307! Your Pull Request "feat(web): enforce keyboard focus trapping in custom modals(closes #2090)" has been successfully merged by @dipexplorer.

Thank you for your valuable contribution to SahiDawa! 🇮🇳
If this was for GSSoC 2026, your work is officially merged and valid. Keep up the great work and feel free to claim other open issues. 🚀

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