[FEATURE] Move Theme Button to Header as Popup

[Akshit-MMQH]

Problem / Motivation
The current floating theme selector looks detached and affects the clean UI.

Proposed Solution
Move the theme button to the header as a small icon. On click, open a simple popup/dropdown with theme options and reset.

Alternatives considered
Keep floating selector (current, less clean)
Sidebar for themes (too heavy for small action)

Acceptance Criteria
Theme button in header
Popup with theme options + reset
Closes on outside click

[github-actions]

Welcome, @Akshit-MMQH! Thanks for raising the issue.
Soon the maintainers/owner will review it and provide you with feedback/suggestions.
Make sure to star this awesome repository and follow the account!

• DevUI

[Akshit-MMQH]

@fahimahammed please assign soo i can start working on it

[deepshikhatutorials]

Hey @fahimahammed
I want to work on this issue. Can you please add it under Hackoctoberfest-2025?
Moving the theme selector to header will definitely make the UI cleaner and more consistent.
A small popup with theme options and a reset button and sounds perfect- lightweight and user-friendly.
Also closing on outside click will improve the overall problem.
I'd love to help implement or test this feature!
Kindly assign me this issue So that I can start working on it.

[fahimahammed]

@Akshit-MMQH @deepshikhatutorials make pr with your changes