Fix theme initilization issue

[saikiran09-ask]

Description

This PR fixes the theme initialization issue in "frontend/index.html" by improving how the theme state and icon are restored during page load.

What was changed

• Fixed incorrect theme initialization behavior
• Ensured the correct icon appears for dark/light mode
• Improved consistency during theme switching
• Cleaned up theme initialization logic for better maintainability

Related Issue

No linked issue.

Type of change

• Bug fix

Checklist

• I have read CONTRIBUTING.md
• My branch is up to date with "main"
• I have tested the changes locally
• I have not introduced duplicate functionality
• My PR title follows the required format

Testing

• Verified theme toggle works correctly
• Tested dark and light mode initialization
• Confirmed icon updates properly after page reload

Additional Notes

This update improves reliability of the frontend theme system without affecting existing functionality.

Test evidence

• Manual frontend testing completed

• Verified theme initializes correctly on page load

• Tested dark mode and light mode switching

• Confirmed theme icon updates properly

• Reloaded page to ensure theme persistence works correctly

[saikiran09-ask]

Implemented the requested fix for theme initialization and verified dark/light mode behavior manually. Kindly review the PR. Thank you!